WorldWideScience

Sample records for include erosion corrosion

  1. Erosion and corrosion of nuclear power plant materials

    International Nuclear Information System (INIS)

    1994-01-01

    This conference is composed of 23 papers, grouped in 3 sessions which main themes are: analysis of corrosion and erosion damages of nuclear power plant equipment and influence of water chemistry, temperature, irradiations, metallurgical and electrochemical factors, flow assisted cracking, stress cracking; monitoring and control of erosion and corrosion in nuclear power plants; susceptibility of structural materials to erosion and corrosion and ways to improve the resistance of materials, steels, coatings, etc. to erosion, corrosion and cracking

  2. Erosion corrosion in water-steam systems: Causes and countermeasures

    International Nuclear Information System (INIS)

    Heitmann, H.G.; Kastner, W.

    1985-01-01

    For the purpose of a better understanding of erosion corrosion, the physical and chemical principles will be summarized briefly. Then results obtained at KWU in the BENSON test section in tests on test specimens in single-phase flow of fully demineralized water will be presented. The experimental studies provide information about the most important influencing parameters. These include flow rate, fluid temperature and water quality (pH value and oxygen content). In addition, the resistance of various materials is compared, and the resistance of magnetite coatings to erosion corrosion is investigated. Furthermore, tests are presented that will show the extent to which erosion corrosion in power plants can be influenced by chemical measures

  3. Ceramic corrosion/erosion project description

    Energy Technology Data Exchange (ETDEWEB)

    Nakaishi, C.V.; Carpenter, L.K.

    1981-02-01

    As a part of the United States Department of Energy's High Temperature Turbine Technology Program, the Morgantown Energy Technology Center is participating in a Ceramics Corrosion/Erosion Materials Study. Objective is to create a technology base for ceramic materials which could be used by stationary gas power turbines operating with a high-temperature, coal-derived, low-Btu gas products of combustion environment. Two facilities are designed and installed to burn a varying low-Btu coal-derived gas in a controlled manner. This report contains the objectives and testing philosophy as well as the operating, specimen handling, and emergency procedures for the facilities. The facilities were checked out in August/September 1980. Testing is scheduled to begin in late 1980 with completion of 1000 hours of ceramic materials exposure to be completed by early 1981. Most of the enclosed is an update of two METC Information Releases (IR), i.e., IR 442 (1979) Test Plan for Ceramic Corrosion/Erosion Project, and IR 817 (1980) Ceramic Corrosion/Erosion Project Description.

  4. Erosion - corrosion mechanisms of stainless steel UNS S31603

    OpenAIRE

    Rajahram, Shiva Suthan

    2010-01-01

    Solid particle erosion-corrosion is the wear caused by the combined action of the mechanical process of solid particle erosion and the electrochemical process of corrosion. This joint action leads to a synergistic interaction that enhances the wear rate of the material, causing severe problems to engineering components exposed to these aggressive conditions. This poses a problem to designers and engineers, as there are currently no robust models available to predict erosion-corrosion rates du...

  5. Potential for erosion corrosion of SRS high level waste tanks

    International Nuclear Information System (INIS)

    Zapp, P.E.

    1994-01-01

    SRS high-level radioactive waste tanks will not experience erosion corrosion to any significant degree during slurry pump operations. Erosion corrosion in carbon steel structures at reported pump discharge velocities is dominated by electrochemical (corrosion) processes. Interruption of those processes, as by the addition of corrosion inhibitors, sharply reduces the rate of metal loss from erosion corrosion. The well-inhibited SRS waste tanks have a near-zero general corrosion rate, and therefore will be essentially immune to erosion corrosion. The experimental data on carbon steel erosion corrosion most relevant to SRS operations was obtained at the Hanford Site on simulated Purex waste. A metal loss rate of 2.4 mils per year was measured at a temperature of 102 C and a slurry velocity comparable to calculated SRS slurry velocities on ground specimens of the same carbon steel used in SRS waste tanks. Based on these data and the much lower expected temperatures, the metal loss rate of SRS tanks under waste removal and processing conditions should be insignificant, i.e. less than 1 mil per year

  6. Technology development by the U.S. industry to resolve erosion-corrosion

    International Nuclear Information System (INIS)

    Chexal, B.; Dietrich, N.; Horowitz, J.; Layman, W.; Randall, G.; Shevde, V.

    1990-01-01

    Erosion-corrosion is a flow-accelerated corrosion process that leads to wall thinning (metal loss) of steel piping exposed to flowing water or wet steam. The rate of metal loss depends on a complex interplay of several parameters. These parameters include water chemistry, material composition, and hydrodynamics. Erosion-corrosion of plant piping can lead to costly outages and repairs, and can raise concerns about plant reliability and safety. Pipe wall degradation rates as high as 1.5 mm/year have occurred, resulting in pipe ruptures at both fossil and nuclear plants. The Nuclear Management and Resource Council (NUMARC) and EPRI have developed inspection planning methods and tools to help utilities identify areas of piping that might undergo erosion-corrosion. These tools provide utilities with the ability to predict wall thinning and to assess various remedial options. This allows utilities to plan and perform inspections, and to correct problems found during inspection. The U.S. electric power industry has developed the knowledge and the tools needed to protect against erosion-corrosion, and utilities have implemented erosion-corrosion monitoring programs. This paper describes EPRI's technical developments that support the utilities in determining where to inspect for erosion-corrosion. 15 refs, 7 figs

  7. Review of SiCf/SiCm corrosion, erosion and erosion-corrosion in high temperature helium relevant to GFR conditions

    Science.gov (United States)

    Fitzgerald, Kerr; Shepherd, Daniel

    2018-01-01

    The good thermal, mechanical and nuclear properties of silicon carbide composites (SiCf/SiCm) has led to their proposal as a gas-cooled fast reactor (GFR) fuel cladding material. Accordingly, previous studies on the corrosion, erosion and erosion-corrosion of SiCf/SiCm have been reviewed. A significant amount of corrosion data was compared for various SiCf/SiCm types tested under different conditions, which suggested that it may be suitable for use in a GFR. However some issues remain, specifically the potential for removal by oxidation of the pyrolytic carbon (PyC) interphase below 900 °C and highly damaging active oxidation at temperatures above 1200 °C. Few relevant papers were found on the erosion and erosion-corrosion behaviour of SiCf/SiCm, though those that were did indicate improved erosion resistance compared to metals. However, most data concerned particulate rather than gas erosion, and at relatively low temperatures. Exacerbation of erosion by corrosion (and vice versa) is hypothesised due to both phenomena potentially causing and being worsened by increased composite porosity. The possibility for this to be further exacerbated mechanically was also identified e.g. by surface damage or by crack formation and growth. The potential impact of irradiation in fast reactor conditions also needs to be better understood. Overall, limited data was found that is representative of anticipated GFR conditions and only in the form of separate effect corrosion tests, thus highlighting the need for erosion and combined effect experiments to progress SiCf/SiCm towards qualification as GFR fuel cladding. Finally, some potential means for improving performance have been identified including environmental adjustment and/or alternative composite design.

  8. Friction surfacing for enhanced surface protection of marine engineering components: erosion-corrosion study

    Science.gov (United States)

    Rajakumar, S.; Balasubramanian, V.; Balakrishnan, M.

    2016-08-01

    Good mechanical properties combined with outstanding corrosion-resistance properties of cast nickel-aluminum bronze (NAB) alloy lead to be a specific material for many marine applications, including ship propellers. However, the erosion-corrosion resistance of cast-NAB alloy is not as good as wrought NAB alloy. Hence, in this investigation, an attempt has been made to improve the erosion-corrosion resistance of cast NAB alloy by depositing wrought (extruded) NAB alloy applying the friction surfacing (FS) technique. Erosion-corrosion tests were carried out in slurries composed of sand particles of 3.5% NaCl solution. Silica sand having a nominal size range of 250-355 μm is used as an erodent. Specimens were tested at 30° and 90° impingement angles. It is observed that the erosion and erosion-corrosion resistance of friction surfaced NAB alloy exhibited an improvement as compared to cast NAB alloy. Scanning electron microscope (SEM) analysis showed that the erosion tracks developed on the cast NAB alloy were wider and deeper than those formed on the friction surfaced extruded NAB alloy.

  9. Synergistic erosion/corrosion of superalloys in PFB coal combustor effluent

    Science.gov (United States)

    Benford, S. M.; Zellars, G. R.; Lowell, C. E.

    1981-01-01

    Two Ni-based superalloys were exposed to the high velocity effluent of a pressurized fluidized bed coal combustor. Targets were 15 cm diameter rotors operating at 40,000 rpm and small flat plate specimens. Above an erosion rate threshold, the targets were eroded to bare metal. The presence of accelerated oxidation at lower erosion rates suggests erosion/corrosion synergism. Various mechanisms which may contribute to the observed oxide growth enhancement include erosive removal of protective oxide layers, oxide and subsurface cracking, and chemical interaction with sulfur in the gas and deposits through damaged surface layers.

  10. Erosion-Corrosion Property of CeO2-Modified HVOF WC-Co Coating

    Science.gov (United States)

    Liu, Yan; Hang, Zongqiu; Chen, Hui; Ceng, Shengbo; Gou, Guoqing; Wang, Xiaomin; Tu, Mingjing; Wu, Xiangyang

    2016-04-01

    Rare-earth elements have been widely used in materials manufacturing to improve hardness and toughness. In this work, conventional, nanostructured, and CeO2-modified WC-12Co powders were sprayed using high-velocity oxygen flame spraying. The erosion-corrosion behavior and interaction of erosion and corrosion of the coatings in 3.5 wt.% NaCl solution were investigated. In situ observation was employed to analyze the failure mechanism. The results showed that the CeO2-modified WC-12Co coating possessed the best erosion-corrosion resistance, while the lowest corrosion resistance was exhibited by the conventional WC-12Co coating. The results also suggested that the erosion-corrosion mechanism in the three coatings was dominated by corrosion-accelerated erosion. However, the extent of acceleration of erosion by corrosion differed.

  11. Single phase and two phase erosion corrosion in broilers of gas-cooled reactors

    International Nuclear Information System (INIS)

    Harrison, G.S.; Fountain, M.J.

    1988-01-01

    Erosion-corrosion is a phenomenon causing metal wastage in a variety of locations in water and water-steam circuits throughout the power generation industry. Erosion-corrosion can occur in a number of regions of the once-through boiler designs used in the later Magnox and AGR type of gas cooled nuclear reactor. This paper will consider two cases of erosion-corrosion damage (single and two phase) in once through boilers of gas cooled reactors and will describe the solutions that have been developed. The single phase problem is associated with erosion-corrosion damage of mild steel downstream of a boiler inlet flow control orifice. With metal loss rates of up to 1 mm/year at 150 deg. C and pH in the range 9.0-9.4 it was found that 5 μg/kg oxygen was sufficient to reduce erosion-corrosion rates to less than 0.02 mm/year. A combined oxygen-ammonia-hydrazine feedwater regime was developed and validated to eliminate oxygen carryover and hence give protection from stress corrosion in the austenitic section of the AGR once through boiler whilst still providing erosion-corrosion control. Two phase erosion-corrosion tube failures have occurred in the evaporator of the mild steel once through boilers of the later Magnox reactors operating at pressures in the range 35-40 bar. Rig studies have shown that amines dosed in the feedwater can provide a significant reduction in metal loss rates and a tube lifetime assessment technique has been developed to predict potential tube failure profiles in a fully operational boiler. The solutions identified for both problems have been successfully implemented and the experience obtained following implementation including any problems or other benefits arising from the introduction of the new regimes will be presented. Methods for monitoring and evaluating the efficiency of the solutions have been developed and the results from these exercises will also be discussed. Consideration will also be given to the similarities in the metal loss

  12. Corrosion and Erosion-Corrosion Processes of Metal-Matrix Composites in Slurry Conditions

    Science.gov (United States)

    Flores, J. F.; Neville, A.; Kapur, N.; Gnanavelu, A.

    2012-03-01

    The corrosion and erosion-corrosion (EC) processes of four metal-matrix composites (MMCs) in a simulated cooling water environment have been assessed in this article. The MMCs consisted of two Ni-base and two Fe-base matrices alloyed with different concentrations of chromium, molybdenum, boron, silicon, and carbon; the matrices were reinforced with tungsten carbide (WC) particles. The corrosion behavior has been investigated using a combination of potentiostatic polarization and post-tests surface analysis. The EC processes were studied by in situ electrochemical techniques measuring the current density and corrosion potential response at different slurry temperatures and sand content. At static conditions it was found that as the temperature increased, there was a transition from a homogeneous corrosion of the matrix to an interfacial corrosion mechanism. The Ni-base MMCs showed a better corrosion resistance and interestingly a highly alloyed matrix did not significantly improved MMC's corrosion resistance. In the in situ EC tests, the Fe-base MMCs showed a constant increase in the current density at all sand contents. Whereas, significant changes were not observed in the Ni-base MMCs below 0.5 g/L. Although sand content had an effect on the monitored current density (the current increased as the sand content increased) this effect was less pronounced above 3 g/L.

  13. Design Mixers to Minimize Effects of Erosion and Corrosion Erosion

    Directory of Open Access Journals (Sweden)

    Julian Fasano

    2012-01-01

    Full Text Available A thorough review of the major parameters that affect solid-liquid slurry wear on impellers and techniques for minimizing wear is presented. These major parameters include (i chemical environment, (ii hardness of solids, (iii density of solids, (iv percent solids, (v shape of solids, (vi fluid regime (turbulent, transitional, or laminar, (vii hardness of the mixer's wetted parts, (viii hydraulic efficiency of the impeller (kinetic energy dissipation rates near the impeller blades, (ix impact velocity, and (x impact frequency. Techniques for minimizing the wear on impellers cover the choice of impeller, size and speed of the impeller, alloy selection, and surface coating or coverings. An example is provided as well as an assessment of the approximate life improvement.

  14. Remote erosion and corrosion monitoring of subsea pipelines using acoustic telemetry and wet-mate connector technology

    Energy Technology Data Exchange (ETDEWEB)

    Painter, Howard; Barlow, Stewart [Teledyne ODI, Thousand Oaks, CA (United States); Clarke, Daniel [Teledyne Cormon, Thousand Oaks, CA (United States); Green, Dale [Teledyne Benthos, North Falmouth, MA (United States)

    2009-07-01

    This paper will present a novel approach for monitoring erosion and corrosion using proven sub sea technologies: intrusive erosion and corrosion monitoring, acoustic telemetry and wet-mateable connector technology. Intrusive metal loss based monitoring systems on sub sea pipelines are increasingly being used because of their ability to directly measure erosion and corrosion. These systems are integrated with the sub sea production control system or located close to the platform and hard-wired. However, locations remote from a sub sea control system or platform requires a dedicated communication system and long lengths of cable that can be cost prohibitive to procure and install. The system presented consists of an intrusive erosion or corrosion monitor with pressure and temperature transmitters, a retrievable electronics module with an acoustic modem, a data storage module, and a replaceable power module. Time-stamped erosion and corrosion data can be transmitted via an acoustic link to a surface platform, a vessel of opportunity or to a relaying modem. Acoustic signals can be transmitted up to 6 km from the monitoring location. The power module along with data module and acoustic modem are mounted on the erosion and corrosion module using wet-mateable connectors, allowing retrieval by remotely operated vehicles. The collected data can be used to assess the cumulative erosion and corrosion as well as use the real-time metal loss rate data to correlate with operational parameters. Benefits include optimization of corrosion inhibitor dosage rates, mitigation of damage caused by solids production, and increased flow assurance. (author)

  15. Erosion-Corrosion Management System for secondary circuits of Nuclear Power Plants

    International Nuclear Information System (INIS)

    Butter, L.M.; Zeijseink, A.G.L.

    2001-01-01

    Erosion-corrosion in water steam systems is a corrosion mechanism that may develop undetected and results in unexpected damages. It is well known which chemical and physical parameters play an important role and what areas are usually affected. In order to facilitate this monitoring of Erosion-corrosion (EC) progress, KEMA has by order of the European Union Tacis-programme developed an Erosion-Corrosion Management System (ECMS) to improve control on the erosion-corrosion process, by improved data handling and analysis. This ECMS has been installed at the South Ukrainian Nuclear Power Plant (SUNPP) - VVER-1000. In general, it has been determined that the current ECMS helps by controlling the erosion-corrosion progress. The ECMS presents and analyses the results on an appropriate way. The recommendations are valuable. (R.P.)

  16. Overview of Corrosion, Erosion, and Synergistic Effects of Erosion and Corrosion in the WTP Pre-treatment Facility

    Energy Technology Data Exchange (ETDEWEB)

    Imrich, K. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-03-27

    Corrosion is an extremely complex process that is affected by numerous factors. Addition of a flowing multi-phase solution further complicates the analysis. The synergistic effects of the multiple corrosive species as well as the flow-induced synergistic effects from erosion and corrosion must be thoroughly evaluated in order to predict material degradation responses. Public domain data can help guide the analysis, but cannot reliably provide the design basis especially when the process is one-of-a-kind, designed for 40 plus years of service, and has no viable means for repair or replacement. Testing in representative simulants and environmental conditions with prototypic components will provide a stronger technical basis for design. This philosophy was exemplified by the Defense Waste Processing Facility (DWPF) at the Savannah River Site and only after 15 plus years of successful operation has it been validated. There have been “hiccups”, some identified during the cold commissioning phase and some during radioactive operations, but they were minor and overcome. In addition, the system is robust enough to tolerate most flowsheet changes and the DWPF design allows minor modifications and replacements – approaches not available with the Hanford Waste Treatment Plant (WTP) “Black Cell” design methodology. Based on the available data, the synergistic effect between erosion and corrosion is a credible – virtually certain – degradation mechanism and must be considered for the design of the WTP process systems. Testing is recommended due to the number of variables (e.g., material properties, process parameters, and component design) that can affect synergy between erosion and corrosion and because the available literature is of limited applicability for the complex process chemistries anticipated in the WTP. Applicable testing will provide a reasonable and defensible path forward for design of the WTP Black Cell and Hard-to-Reach process equipment. These

  17. Surface Modelling of Nanostructured Copper Subjected to Erosion-Corrosion

    Directory of Open Access Journals (Sweden)

    Osama M. Irfan

    2017-04-01

    Full Text Available The last decade has witnessed considerable advancements in nanostructured material synthesis and property characterization. However, there still exists some deficiency in the mechanical and surface property characterization of these materials. In this paper, the erosion corrosion (E-C behavior of nanostructured copper was studied. The nanostructured copper was produced through severe plastic deformation (SPD by applying four passes of equal channel angular pressing (ECAP. The combined effects of the testing time, impact velocity, and concentration of erosive solid particles (i.e., sand concentration on the E-C behavior of nanostructured copper were then examined. Based on a defined domain for the testing time, impact velocity, and sand concentration, E-C tests were performed for numerous combinations of test points via the slurry pot method. The test points were selected using the face-centered center composite design of experiments to enable visualization of the test results through surface plots. The extent of E-C on the test specimens was determined by measuring the mass loss. Polynomial regression and Kriging were used to fit surfaces to the experimental data, which were subsequently used to generate surface plots. The results showed that the E-C of nanostructured copper is best described by a quadratic function of testing time, velocity, and erosive solid particle concentration. The results also revealed that E-C increases with an increasing testing time, impact velocity, and erosive solid particle concentration. In addition, it was observed that the effect of the erosive solid particles on E-C is further intensified by an increased impact velocity.

  18. Testing and prediction of erosion-corrosion for corrosion resistant alloys used in the oil and gas production industry

    Science.gov (United States)

    Rincon, Hernan E.

    The corrosion behavior of CRAs has been thoroughly investigated and documented in the public literature by many researchers; however, little work has been done to investigate erosion-corrosion of such alloys. When sand particles are entrained in the flow, the degradation mechanism is different from that observed for sand-free corrosive environment. There is a need in the oil and gas industry to define safe service limits for utilization of such materials. The effects of flow conditions, sand rate, pH and temperature on the erosion-corrosion of CRAs were widely studied. An extensive experimental work was conducted using scratch tests and flow loop tests using several experimental techniques. At high erosivity conditions, a synergistic effect between erosion and corrosion was observed. Under the high sand rate conditions tested, erosivity is severe enough to damage the passive layer protecting the CRA thereby enhancing the corrosion rate. In most cases there is likely a competition between the rates of protective film removal due to mechanical erosion and protective film healing. Synergism occurs for each of the three alloys examined (13Cr and Super13Cr and 22Cr); however, the degree of synergism is quite different for the three alloys and may not be significant for 22Cr for field conditions where erosivities are typically much lower that those occurring in the small bore loop used in this research. Predictions of the corrosion component of erosion-corrosion based on scratch test data compared reasonably well to test results from flow loops for the three CRAs at high erosivity conditions. Second order behavior appears to be an appropriate and useful model for representing the repassivation process of CRAs. A framework for a procedure to predict penetration rates for erosion-corrosion conditions was developed based on the second order model behavior observed for the re-healing process of the passive film of CRAs and on computational fluid dynamics (CFD) simulations

  19. Workshop on Copper Corrosion and Buffer Erosion. Stockholm 15-17 September 2010

    International Nuclear Information System (INIS)

    Robinson, Peter; Bath, Adrian

    2011-02-01

    the buffer erosion and related corrosion scenario. Because of its potential significance and recent prominence and with the insights already provided by the BRITE group's review of the scientific case and experimental evidence, the hypothesis that copper is subject to corrosion reaction with pure water under anoxic conditions was included in the scope of the workshop. The workshop identified a broad number of potential issues and the information required to address the issues, considered their relative significance to EBS performance and to a safety case, and also examined where there might be specific couplings and interdependence between processes that also need to be addressed

  20. Ash formation, deposition, corrosion, and erosion in conventional boilers

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S.A.; Jones, M.L. [Univ. of North Dakota, Grand Forks, ND (United States)

    1995-12-01

    The inorganic components (ash-forming species) associated with coals significantly affect boiler design, efficiency of operation, and lifetimes of boiler parts. During combustion in conventional pulverized fuel boilers, the inorganic components are transformed into inorganic gases, liquids, and solids. This partitioning depends upon the association of the inorganic components in the coal and combustion conditions. The inorganic components are associated as mineral grains and as organically associated elements, and these associations of inorganic components in the fuel directly influence their fate upon combustion. Combustion conditions, such as temperature and atmosphere, influence the volatility and the interaction of inorganic components during combustion and gas cooling, which influences the state and size composition distribution of the particulate and condensed ash species. The intermediate species are transported with the bulk gas flow through the combustion systems, during which time the gases and entrained ash are cooled. Deposition, corrosion, and erosion occur when the ash intermediate species are transported to the heat-transfer surface, react with the surface, accumulate, sinter, and develop strength. Research over the past decade has significantly advanced understanding of ash formation, deposition, corrosion, and erosion mechanisms. Many of the advances in understanding and predicting ash-related issues can be attributed to advanced analytical methods to determine the inorganic composition of fuels and the resulting ash materials. These new analytical techniques have been the key to elucidation of the mechanisms of ash formation and deposition. This information has been used to develop algorithms and computer models to predict the effects of ash on combustion system performance.

  1. Erosion-Corrosion Behavior of Power Plant Pipe Caused by Hot Feed Water

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Sungho; Lee, Jinwon; Kim, Taewon [Hanyang Univ., Seoul (Korea, Republic of)

    2013-06-15

    In this study, we tried to define the erosion-corrosion behavior together with the resulting effects on a pipe that is a part of a feed water circulation system according to the pipe size and hot feed water environment. An erosion corrosion analysis was performed through the Hayduk and Minas model based on the chemical reaction between iron and oxygen, an essential corrosive factor. The erosion-corrosion rate against the pipe diameter and feed water temperature was then evaluated by means of finite element analysis using Abacus. As shown in the results, the feed water temperature was the main factor influencing the erosion-corrosion rate; in particular, it was expected that the thickness of 316 stainless steel would decrease by 2.59 {mu}m every year in a hot water environment at 290 .deg. C.

  2. Erosion-corrosion resistance of engineering materials in various test conditions

    OpenAIRE

    Rajahram, S.S; Harvey, T.J.; Wood, R.J.K.

    2009-01-01

    Erosion–corrosion is a complex phenomenon which involves the interaction between the mechanical processes of solid particle erosion and the electrochemical processes of corrosion. A whole range of issues is faced by a designer when trying to obtain relevant information on erosion–corrosion performance of a material. Amongst the constraints are the dispersed test conditions and test rigs available in the literature making comparisons and quantifying erosion–corrosion wear rates of different ma...

  3. Erosion-corrosion of 316 stainless steel rods immersed in a bubbling fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.Y.; Coronella, C.J.; Seader, J.D. (Utah Univ., Salt Lake City, UT (United States). Dept. of Chemical Engineering); Pitt, C.H. (Utah Univ., Salt Lake City, UT (United States). Dept. of Metallurgy and Metallurgical Engineering)

    1993-04-01

    A fluidized bed was operated in the bubbling regime with sand to determine the effects of process variables on in-bed metal wastage due to erosion and/or corrosion of immersed 316 stainless steel (SS) rods. Weight loss as a result of erosion was determined by conducting experiments with air at room temperature and high fluidizing velocities (erosion-dominated). Weight loss due mainly to corrosion was determined by carrying out wear tests at 500[sup o]C and relatively low gas velocity (corrosion-dominated). By comparing the total weight loss obtained from the tests at high temperature and high gas velocity conditions (erosion-corrosion-dominated) with the sum of weight losses from erosion-dominated and corrosion-dominated studies, it was found that there was a synergistic effect between corrosion and erosion, i.e. erosion and corrosion took place simultaneously and interacted in a way leading to accelerated wear of the 316 SS rods. The wear rates increased with increasing temperature and excess gas velocity and were also affected by rod orientation in that wear rates of vertical rods were less than those of horizontal rods under identical test conditions. In all cases, wear rates were less than 3.0 nm/h in the radial direction. (author)

  4. Numerical simulation and factor analysis of petrochemical pipe erosion-corrosion failure

    Science.gov (United States)

    XU, G. F.; OU, G. F.; Chen, T.; Li, P. X.; JIN, H. Z.

    2016-05-01

    Based on the behavior of carbon steel outlet tube in REAC pipes of Zhenhai Refining & Chemical Company, the mathematical model of fluid-solid interaction was established according to the mechanism of erosion-corrosion damage. The interaction between corrosion products protecting film and multiphase liquid was analyzed by numerical simulation method. The distribution of shearing stress on the inwall of elbow bend, and the distribution of principal displacement, stress and strain of corrosion products protecting film were disclosed, while the erosion-corrosion failure processes was studied. The simulation result coincides with that of the positioned thickness gauging which validated the reliability and feasibility of the finite element analysis software simulation method. The obtained results can be used in the erosion-corrosion failure analysis, structural optimization, in-service testing positioning, life prediction, risk assessment, safety and other security projects for multiphase flow pipeline.

  5. Lithium-system corrosion/erosion studies for the FMIT project

    Energy Technology Data Exchange (ETDEWEB)

    Bazinet, G D [comp.

    1983-04-01

    The corrosion behavior of selected materials in a liquid lithium environment has been studied in support of system and component designs for the Fusion Materials Irradiation Test (FMIT) Facility. The liquid lithium test resources and the capabilities of several laboratories were used to study specific concerns associated with the overall objective. Testing conditions ranged from approx. 3700 hours to approx. 6500 hours of exposure to flowing lithium at temperatures from 230/sup 0/C to 270/sup 0/C and static lithium at temperatures from 200/sup 0/C to 500/sup 0/C. Principal areas of investigation included lithium corrosion/erosion effects of FMIT lithium system materials (largely Type 304 and Type 304L austenitic stainless steels) and candidate materials for major system components.

  6. Lithium-system corrosion/erosion studies for the FMIT project

    International Nuclear Information System (INIS)

    Bazinet, G.D.

    1983-04-01

    The corrosion behavior of selected materials in a liquid lithium environment has been studied in support of system and component designs for the Fusion Materials Irradiation Test (FMIT) Facility. The liquid lithium test resources and the capabilities of several laboratories were used to study specific concerns associated with the overall objective. Testing conditions ranged from approx. 3700 hours to approx. 6500 hours of exposure to flowing lithium at temperatures from 230 0 C to 270 0 C and static lithium at temperatures from 200 0 C to 500 0 C. Principal areas of investigation included lithium corrosion/erosion effects of FMIT lithium system materials (largely Type 304 and Type 304L austenitic stainless steels) and candidate materials for major system components

  7. Erosion-corrosion in carbon dioxide saturated systems in presence of sand, inhibitor, oil, and high concentration of salt

    Science.gov (United States)

    Hassani, Shokrollah

    Oil and gas production is usually accompanied by formation water which typically contains high levels of chloride. Some effects of chloride concentration on corrosion are not widely known in the literature, and this can result in misleading conclusions. One goal of this research was to contribute to a better understanding of the effects of chloride concentration in CO2 corrosion. Experimental and theoretical studies conducted in the present work have shown that increasing the NaCl concentration in solution has three important effects on corrosion results. First, standard pH meter readings in high NaCl concentration solutions require corrections. Second, increasing the NaCl concentration decreases the CO2 concentration in solution and therefore contributes to a decrease in the corrosion rate. Third, increasing the NaCl concentration increases the solubility of FeCO3 and therefore reduces the likelihood of forming an iron carbonate scale. High NaCl concentration also decreases the sand erosion rate of the metal slightly by increasing the density and viscosity of the liquid. There are two main contributions of this research. The first contribution is the experimental characterization of inhibited erosion-corrosion behavior of mild steel under CO2-saturated conditions with a high salt concentration. Chemical inhibition is one the most important techniques for controlling erosion-corrosion in offshore mild steel pipelines, tubing and pipe fittings in oil and gas industry. The second contribution is the introduction of a new approach for predicting inhibited erosion-corrosion in mild steel pipes including the effects of flow and environmental conditions, sand production, and an oil phase. Sand erosion can decrease the efficiency of corrosion protection systems including iron-carbonate scale formation and chemical inhibition. The need to be able to predict inhibitor performance under sand production conditions is particularly acute when the wells are deep or off

  8. Study of corrosive-erosive wear behaviour of Al6061/albite composites

    International Nuclear Information System (INIS)

    Sharma, S.C.; Krishna, M.; Murthy, H.N. Narasimha; Tarachandra, R.; Satyamoorthy, M.; Bhattacharyya, D.

    2006-01-01

    This investigation analyses the influence of dispersed alumina particles on the wear behaviour of the Al/albite composites in a corrosive environment. The composites were prepared by modified pressure die-casting technique. The corrosive-erosive wear experiments were carried out on a proprietary corrosion-erosion wear tester to study the wear characteristics of the composites. The slurry was made up of water and alumina (size: 90-150 μm, proportion: 0-30 wt.%), while H 2 SO 4 (0.01, 0.1 and 1N) was added to create the corrosive conditions. Experiments were arranged to test the relationships among the corrosive-erosive wear rate, concentrations of H 2 SO 4 and alumina in the slurry, weight percent of albite in the composite, erosion speed and distance. Wear rate varies marginally at low speeds but sharply increases at higher speeds. The corrosive wear rate logarithmically increased with the increasing concentration of the corrosive medium. The effect of abrasive particles and corrosion medium on the wear behaviour of the composite is explained experimentally, theoretically and using scanning electron microscopy

  9. An experimental study on cavitation erosion-corrosion performance of ANSI 1020 and ANSI 4135 steel

    International Nuclear Information System (INIS)

    Wang, Leqin; Qiu, Ning; Hellmann, Dieter-Heinz; Zhu, Xiaowen

    2016-01-01

    Cavitation erosion is quite complex, containing corrosion-erosion interaction effect. High temperature oxidization may be aroused after bubble collapse, accompanied by hot gas contacting with the pump component surface. The analysis of the erosion pits can be an effective way to know the mechanism of cavitation erosion. In present paper, the cavitation erosion resistance of carbon steel (ANSI 1020) and alloy steel (ANSI 4135) were tested in an ultrasonic vibration apparatus. By using energy dispersive X-ray spectroscope and three dimensional laser microscope, the chemical composition around erosion pits and the oxidation film structure were analyzed. By using metallographic microscope and scanning electronic microscope, the metallographic structure of specimens (e.g., carbon steel and alloy steel), the nano structured iron oxide and corresponding influence on specimen's anti-erosion performance were discussed. Based on the comparison between the different tests performed in distilled water and tap water respectively, results can be obtained that erosion rate of carbon steel and alloy steel varies with the component of water which had close correlation to the oxidation effect. Erosion rate of alloy steel 4135 was much lower in distilled water compared to tap water while the difference of carbon steel 1020 was not that large. The remarkable different responses of these two materials had close relationship with oxidation effect. The oxidation effect transferred the original structure of alloy steel surface which had high anti-erosion capability, into newly generated iron oxide structure, which was preferentially to be attacked. The pumping of slightly corrosive fluids frequently leads to erosion-corrosion damage on impellers, and corrosion can further amplify the erosion process

  10. Identified corrosion and erosion mechanisms in SCO2 Brayton Cycles.

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Darryn D.; Kruizenga, Alan Michael

    2014-06-01

    Supercritical Carbon Dioxide (S-CO2) is an efficient and flexible working fluid for power production. Research to interface S-CO2 systems with nuclear, thermal solar, and fossil energy sources is currently underway. To proceed, we must address concerns regarding compatibility of materials, at high temperature, and compatibility between significantly different heat transfer fluids. Dry, pure S-CO2 is thought to be relatively inert [1], while the addition of ppm levels of water and oxygen result in formation of a protective chromia layer and iron oxide [2]. Thin oxides are favorable as diffusion barriers, and for their minimal impact on heat transfer. While S-CO2 is typically understood to be the secondary fluid, many varieties of primary fluids exist for nuclear applications. Molten salts, for use in the Molten Salt Reactor concept, are given as an example to contrast the materials requirements of primary and secondary fluids. Thin chromia layers are soluble in molten salt systems (nitrate, chloride, and fluoride based salts) [3-8], making materials selection for heat exchangers a precarious balancing act between high temperature oxidation (S-CO2) and metal dissolution (salt side of heat exchanger). Because concerns have been raised regarding component lifetimes, S-CO2 work has begun to characterize starting materials and to establish a baseline by analysis of 1) as-received stainless steel piping, and 2) piping exposed to S-CO2 under typical operating conditions with Sandia National Laboratories Brayton systems. A second issue discovered by SNL involves substantial erosion in the turbine blade and inlet nozzle. It is believed that this is caused by small particulates that originate from different materials around the loop that are entrained by the S-CO2 to the nozzle, where they impact the inlet nozzle vanes, causing erosion. We believe that, in some way, this is linked to the purity of the S-CO2, the corrosion contaminants, and the metal particulates that

  11. Corrosion and erosion properties of silicate and phosphate coatings on magnesium

    International Nuclear Information System (INIS)

    Ma, Y.; Nie, X.; Northwood, D.O.; Hu, H.

    2004-01-01

    Electrolytic plasma processing (EPP) is an emerging, environmentally friendly, surface engineering technique. In this study, we have utilized the EPP technique to deposit silicate and phosphate coatings on magnesium for both corrosion and erosion protection. Potentiodynamic polarization measurements were used to investigate the corrosion properties of the coated samples. A stirring device was also used for corrosion and erosion testing. Coated and uncoated samples were immersed in a 3.5 wt.% NaCl solution with SiO 2 sand in suspension and rotated at a given speed. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis were used to study surface morphology and chemical composition of the coatings before and after corrosion-erosion testing

  12. Exceptionally high cavitation erosion and corrosion resistance of a high entropy alloy.

    Science.gov (United States)

    Nair, R B; Arora, H S; Mukherjee, Sundeep; Singh, S; Singh, H; Grewal, H S

    2018-03-01

    Cavitation erosion and corrosion of structural materials are serious concerns for marine and offshore industries. Durability and performance of marine components are severely impaired due to degradation from erosion and corrosion. Utilization of advanced structural materials can play a vital role in limiting such degradation. High entropy alloys (HEAs) are a relatively new class of advanced structural materials with exceptional properties. In the present work, we report on the cavitation erosion behavior of Al 0.1 CoCrFeNi HEA in two different media: distilled water with and without 3.5wt% NaCl. For comparison, conventionally used stainless steel SS316L was also evaluated in identical test conditions. Despite lower hardness and yield strength, the HEA showed significantly longer incubation period and lower erosion-corrosion rate (nearly 1/4th) compared to SS316L steel. Enhanced erosion resistance of HEA was attributed to its high work-hardening behavior and stable passivation film on the surface. The Al 0.1 CoCrFeNi HEA showed lower corrosion current density, high pitting resistance and protection potential compared to SS316L steel. Further, HEA showed no evidence of intergranular corrosion likely due to the absence of secondary precipitates. Although, the degradation mechanisms (formation of pits and fatigue cracks) were similar for both the materials, the damage severity was found to be much higher for SS316L steel compared to HEA. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Analysis of Barrier Performance: Modelling of Copper corrosion scenarios with and without buffer erosion

    International Nuclear Information System (INIS)

    Benbow, Steven J.; Robinson, Peter C.; Watson, Sarah P.

    2011-02-01

    SKB have identified buffer erosion as a process that could potentially lead to increased corrosion of the copper canister. Buffer erosion can be caused by: the formation of bentonite (i.e., montmorillonite) colloids and their transport away from deposition holes in intersecting fractures containing dilute groundwaters (such as subglacial meltwaters); steep hydraulic gradients during buffer resaturation; or shearing of solid bentonite particles by rapidly flowing groundwater. Only colloidal removal of bentonite (the first of the processes listed) is considered in this study. The erosion of the bentonite leads to a reduction in density and swelling potential, and hence a lowering of transport resistances in the buffer that can make it easier for corrosive agents to transported to be the canister surface, resulting in increased levels of corrosion of the canister surface compared with those predicted in 'normal evolution' conditions. The reduction in bentonite density that follows as a consequence of erosion also leads to the possibility of breaching other safety functions of the buffer, for example prevention of canister sinking and resistance to shear deformation. These are not considered in this study. This report describes the modelling of copper corrosion processes in the SKB KBS-3 design concept. The modelling includes an initial representation of all relevant physical processes, but with some processes represented in more detail than others. This allows investigation of the impacts of the processes that are modelled on canister corrosion, allowing identification of the processes that impact most on the key performance measures for the EBS, which will help to focus modelling developments in future work. This work could be taken as the starting point in a longer-term modelling study in which the interactions between processes that affect canister corrosion are further investigated. Two high-level scenarios are considered in this work: a base case scenario in

  14. Effects of chemistry on corrosion-erosion of steels in water and wet steam

    International Nuclear Information System (INIS)

    Berge, P.; Ducreux, J.; Saint-Paul, P.

    1981-01-01

    In steam production plants, numerous cases of degradation of steels occur when in contact with water or wet steam circulating at high velocity: in feed or discharge pumps, water reheaters, etc. When the phenomenon occurs without any mechanical wear of the metal or the oxide from the impact of solid particles (abrasion) or droplets (erosion), it is called corrosion-erosion. The phenomenon usually occurs between 100 and 250 0 C, as has been confirmed by an empirical study of the thermal and hydraulic factors which govern it. Corrosion rates can reach 1 to 2 mm/year, for a carbon steel pipe where water treated with ammonia circulates at about pH 9, at 200 0 C, and at a velocity of 5 to 10 m/s. This study evaluates the part played by the factors solely connected to the chemistry of water, with respect to the kinetics of the corrosion-erosion phenomenon. (author)

  15. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

    Presents some materials for use in demonstration and experimentation of corrosion processes, including corrosion stimulation and inhibition. Indicates that basic concepts of electrochemistry, crystal structure, and kinetics can be extended to practical chemistry through corrosion explanation. (CC)

  16. Erosion-corrosion in water steam cycles. Causes and counter measures

    International Nuclear Information System (INIS)

    Heitmann, H.G.; Kastner, W.

    1984-01-01

    An increased material erosion on tubes in steam generators, feedheaters and condensers but also of turbine casings and interconnecting pipes made of unalloyed and low-alloy steels is essentially due to erosion-corrosion processes in the fluid-swept plant sections, they cause thinning of the material and sometimes leaks and impurities in the water-steam cycle. The cause of erosion-corrosion is a dissolving corrosion due to the convective effect of pure fluid turbulences. The occurrence is limited to metallic materials, the constancy of which depends on oxide protection layers. The cover layers are destroyed by erosive influence. At KWU, experimental studies of plates were carried out in the Benson test section to obtain information about the most important parameters; flow velocity fluid temperature and water quality (pH value and oxygen content). Moreover, the resistance of different materials is compared and the resistance of magnetite protection layers to erosion-corrosion is examined. The following design features reveal to be important: use of chromium alloy materials, reduction of the flow velocity, increase in the pH value or the oxygen content

  17. Plasma nitriding of a precipitation hardening stainless steel to improve erosion and corrosion resistance

    International Nuclear Information System (INIS)

    Cabo, Amado; Bruhl, Sonia P.; Vaca, Laura S.; Charadia, Raul Charadia

    2010-01-01

    Precipitation hardening stainless steels are used as structural materials in the aircraft and the chemical industry because of their good combination of mechanical and corrosion properties. The aim of this work is to analyze the structural changes produced by plasma nitriding in the near surface of Thyroplast PH X Supra®, a PH stainless steel from ThyssenKrupp, and to study the effect of nitriding parameters in wear and corrosion resistance. Samples were first aged and then nitriding was carried out in an industrial facility at two temperatures, with two different nitrogen partial pressures in the gas mixture. After nitriding, samples were cut, polished, mounted in resin and etched with Vilella reagent to reveal the nitrided case. Nitrided structure was also analyzed with XRD. Erosion/Corrosion was tested against sea water and sand flux, and corrosion in a salt spray fog (ASTM B117). All nitrided samples presented high hardness. Samples nitrided at 390 deg C with different nitrogen partial pressure showed similar erosion resistance against water and sand flux. The erosion resistance of the nitrided samples at 500 deg C was the highest and XRD revealed nitrides. Corrosion resistance, on the contrary, was diminished; the samples suffered of general corrosion during the salt spray fog test. (author)

  18. Effects of oxidation and hot corrosion on the erosion of silicon nitride

    International Nuclear Information System (INIS)

    Kim, Jong Jip

    2005-01-01

    The effect of oxidation and hot corrosion on the solid particle erosion was investigated for hot-pressed silicon nitride using as- polished, pre-oxidized and pre-corroded specimens by molten sodium sulfates. Erosion tests were performed at 22, 500 and 900 .deg. C using angular silicon carbide particles of mean diameter 100 μm. Experimental results show that solid particle erosion rate of silicon nitride increases with increasing temperature for as-polished or pre-oxidized specimens in consistent with the prediction of a theoretical model. Erosion rate of pre-oxidized specimens is lower than that of as-polished specimens at 22 .deg. C, but it is higher at 900 .deg. C. Lower erosion rate at 22 .deg. C in the pre-oxidized specimens is attributed due to the blunting of surface flaws, and the higher erosion rate at 900 .deg. C is due to brittle lateral cracking. Erosion rate of pre-corroded specimens decreases with increasing temperature. Less erosion at 900 .deg. C than at 22 .deg. C is associated with the liquid corrosion products sealing off pores at 900 .deg. C and the absence of inter-granular crack propagation observed at 22 .deg. C

  19. Corrosion-erosion of steels in high temperature water and wet steam

    International Nuclear Information System (INIS)

    Berge, P.; Khan, F.

    1984-01-01

    This paper summarizes, and concludes specialists' meeting held at Les Renardieres. The corrosion-erosion phenomena of steel in water and wet steam find their origin in an essentially chemical phenomenon, requiring the presence of a permanently renewed liquid phase flowing in contact with the steel. The most frequently encountered temperature range for the corrosion-erosion phenomenon is 150-250 0 C. The estimation of mass transfer coefficient which is necessary to predict the corrosion-erosion rate is often difficult. The suggested mechanism enables to predict the expected variations of kinetics by a modification of the chemical conditions (pH, H 2 , N 2 H 4 , O 2 ). An incubation period due to the preoxidation of the specimen is possible. An addition of chromium and molybdenum (such as in 2 1/4Cr, 1 Mo steels) imparts a corrosion-erosion resistance to steel as compared to the unalloyed steels. The behaviour of these steels is strongly affected by the presence of Cu, Cr and Mo even in trace quantities. (5 tables and 32 references are given) [fr

  20. Study of surface interactions of ionic liquids with aluminium alloys in corrosion and erosion-corrosion processes

    Energy Technology Data Exchange (ETDEWEB)

    Bermudez, Maria-Dolores [Grupo de Ciencia de Materiales e Ingenieria Metalurgica, Departamento de Ingenieria de Materiales y Fabricacion, Universidad Politecnica de Cartagena, C/ Doctor Fleming s/n, Campus Muralla del Mar, 30202 Cartagena (Spain)]. E-mail: mdolores.bermudez@upct.es; Jimenez, Ana-Eva [Grupo de Ciencia de Materiales e Ingenieria Metalurgica, Departamento de Ingenieria de Materiales y Fabricacion, Universidad Politecnica de Cartagena, C/ Doctor Fleming s/n, Campus Muralla del Mar, 30202 Cartagena (Spain); Martinez-Nicolas, Gines [Grupo de Ciencia de Materiales e Ingenieria Metalurgica, Departamento de Ingenieria de Materiales y Fabricacion, Universidad Politecnica de Cartagena, C/ Doctor Fleming s/n, Campus Muralla del Mar, 30202 Cartagena (Spain)

    2007-06-30

    Surface interactions of alkylimidazolium ionic liquids (ILs) with aluminium alloy Al 2011 have been studied by immersion tests in seven neat ILs [1-n-alkyl-3-methylimidazolium X{sup -} (X = BF{sub 4}; n = 2 (IL1), 6 (IL2), 8 (IL3). X = CF{sub 3}SO{sub 3}; n = 2 (IL4). X = (4-CH{sub 3}C{sub 6}H{sub 4}SO{sub 3}); n = 2 (IL5). X PF{sub 6}; n = 6 (IL6)] and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide (IL7)]. Immersion tests for Al 2011 have also been carried out in 1 wt.% and 5 wt.% solutions of 1-ethyl,3-methylimidazolium tetrafluoroborate (IL1) in water. No corrosion of Al 2011 by neat ILs is observed. The highest corrosion rate for Al 2011 in water is observed in the presence of a 5 wt.% IL1 due to hydrolysis of the anion with hydrogen evolution and formation of aluminium fluoride. Erosion-corrosion processes have been studied for three aluminium alloys (Al 2011, Al 6061 and Al 7075) in a 90 wt.% IL1 solution in water in the presence of {alpha}-alumina particles. The erosion-corrosion rates are around 0.2 mm/year or lower, and increase with increasing copper content to give a corrosion resistance order of Al 6061 > Al 7075 > Al 2011. Results are discussed on the basis of scanning electron microscopy (SEM) observations, energy dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD) patterns and X-ray photoelectron spectroscopy (XPS) determinations.

  1. Erosion and corrosion resistance of laser cladded AISI 420 stainless steel reinforced with VC

    Science.gov (United States)

    Zhang, Zhe; Yu, Ting; Kovacevic, Radovan

    2017-07-01

    Metal Matrix Composites (MMC) fabricated by the laser cladding process have been widely applied as protective coatings in industries to improve the wear, erosion, and corrosion resistance of components and prolong their service life. In this study, the AISI 420/VC metal matrix composites with different weight percentage (0 wt.%-40 wt.%) of Vanadium Carbide (VC) were fabricated on a mild steel A36 by a high power direct diode laser. An induction heater was used to preheat the substrate in order to avoid cracks during the cladding process. The effect of carbide content on the microstructure, elements distribution, phases, and microhardness was investigated in detail. The erosion resistance of the coatings was tested by using the abrasive waterjet (AWJ) cutting machine. The corrosion resistance of the coatings was studied utilizing potentiodynamic polarization. The results showed that the surface roughness and crack susceptibility of the laser cladded layer were increased with the increase in VC fraction. The volume fraction of the precipitated carbides was increased with the increase in the VC content. The phases of the coating without VC consisted of martensite and austenite. New phases such as precipitated VC, V8C7, M7C3, and M23C6 were formed when the primary VC was added. The microhardness of the clads was increased with the increase in VC. The erosion resistance of the cladded layer was improved after the introduction of VC. The erosion resistance was increased with the increase in the VC content. No obvious improvement of erosion resistance was observed when the VC fraction was above 30 wt.%. The corrosion resistance of the clads was decreased with the increase in the VC content, demonstrating the negative effect of VC on the corrosion resistance of AISI 420 stainless steel

  2. Erosion and corrosion resistance of laser cladded AISI 420 stainless steel reinforced with VC

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhe [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States); Yu, Ting [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States); School of Mechanical and Electrical Engineering, Nanchang University, Nanchang, Jiangxi 330031 (China); Kovacevic, Radovan, E-mail: kovacevi@smu.edu [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States)

    2017-07-15

    Highlights: • The coatings of 420 stainless steel reinforced with VC were fabricated by high power direct diode laser. • The erosion resistance of the cladded layer was increased with the increase in the VC fraction. • No obvious improvement of erosion resistance was observed when the VC fraction was above 30 wt.%. • The corrosion resistance of the cladded layer was decreased with the increase in the VC fraction. - Abstract: Metal Matrix Composites (MMC) fabricated by the laser cladding process have been widely applied as protective coatings in industries to improve the wear, erosion, and corrosion resistance of components and prolong their service life. In this study, the AISI 420/VC metal matrix composites with different weight percentage (0 wt.%–40 wt.%) of Vanadium Carbide (VC) were fabricated on a mild steel A36 by a high power direct diode laser. An induction heater was used to preheat the substrate in order to avoid cracks during the cladding process. The effect of carbide content on the microstructure, elements distribution, phases, and microhardness was investigated in detail. The erosion resistance of the coatings was tested by using the abrasive waterjet (AWJ) cutting machine. The corrosion resistance of the coatings was studied utilizing potentiodynamic polarization. The results showed that the surface roughness and crack susceptibility of the laser cladded layer were increased with the increase in VC fraction. The volume fraction of the precipitated carbides was increased with the increase in the VC content. The phases of the coating without VC consisted of martensite and austenite. New phases such as precipitated VC, V{sub 8}C{sub 7}, M{sub 7}C{sub 3}, and M{sub 23}C{sub 6} were formed when the primary VC was added. The microhardness of the clads was increased with the increase in VC. The erosion resistance of the cladded layer was improved after the introduction of VC. The erosion resistance was increased with the increase in the VC content

  3. Erosion and corrosion resistance of laser cladded AISI 420 stainless steel reinforced with VC

    International Nuclear Information System (INIS)

    Zhang, Zhe; Yu, Ting; Kovacevic, Radovan

    2017-01-01

    Highlights: • The coatings of 420 stainless steel reinforced with VC were fabricated by high power direct diode laser. • The erosion resistance of the cladded layer was increased with the increase in the VC fraction. • No obvious improvement of erosion resistance was observed when the VC fraction was above 30 wt.%. • The corrosion resistance of the cladded layer was decreased with the increase in the VC fraction. - Abstract: Metal Matrix Composites (MMC) fabricated by the laser cladding process have been widely applied as protective coatings in industries to improve the wear, erosion, and corrosion resistance of components and prolong their service life. In this study, the AISI 420/VC metal matrix composites with different weight percentage (0 wt.%–40 wt.%) of Vanadium Carbide (VC) were fabricated on a mild steel A36 by a high power direct diode laser. An induction heater was used to preheat the substrate in order to avoid cracks during the cladding process. The effect of carbide content on the microstructure, elements distribution, phases, and microhardness was investigated in detail. The erosion resistance of the coatings was tested by using the abrasive waterjet (AWJ) cutting machine. The corrosion resistance of the coatings was studied utilizing potentiodynamic polarization. The results showed that the surface roughness and crack susceptibility of the laser cladded layer were increased with the increase in VC fraction. The volume fraction of the precipitated carbides was increased with the increase in the VC content. The phases of the coating without VC consisted of martensite and austenite. New phases such as precipitated VC, V 8 C 7 , M 7 C 3 , and M 23 C 6 were formed when the primary VC was added. The microhardness of the clads was increased with the increase in VC. The erosion resistance of the cladded layer was improved after the introduction of VC. The erosion resistance was increased with the increase in the VC content. No obvious improvement

  4. Development of improved lacv-30 propeller blade coatings for protection against sand and rain erosion and marine environment corrosion. Final report 4 Jan 1982-4 Mar 1983

    Energy Technology Data Exchange (ETDEWEB)

    Malone, G.A.

    1983-05-10

    An investigation was conducted of candidate systems offering potential erosion and corrosion protection when applied as coatings to Aluminum 7075 alloy propeller blades used to propel air cushioned vehicles operating in severe environments. This work focused on (1) special hard anodized and (2) hard nickel electroplated coatings as candidate protective systems with sand/rain erosion testing to evaluate their merits. Attributes of the coating systems developed and studied included: For (1) Ways and means to produce and control deposit hardness for optimum erosion resistance, methods of bonding to blades for high integrity adhesion, and inclusion of sacrificial corrosion protection electroplates in the coating systems (zinc and zinc-nickel alloy). For (2) Incorporation of dry film lubricant systems on sealed hardcoats of various anodic coating thicknesses to enhance erosion performance. Study results indicated that anodized coatings did not provide suitable erosion protection to Aluminum 7075 in sand/rain environments, even with dry film lubricant supplemental films. Electroplated hard nickel coatings, Vickers hardnesses in the range of 380 to 440, appeared better for combined sand/rain erosion resistance based on comparisons with prior work. Dilute phosphoric anodizing the aluminum substrates led to excellent bonds and improved corrosion resistance when subsequently plated with ductile nickel from a low pH bath, followed by hard nickel electroplate.

  5. Erosion-corrosion problems encountered during the operation of conventional plants

    International Nuclear Information System (INIS)

    Garaud, J.

    1984-01-01

    Are reported three experiments carried out in order to fight erosion-corrosion by a pH analysis on the heat exchangers of the plant Saint-Laurent-des-Eaux A, on the low pressure reheaters of conventional flame plants and on the reheater-separator vessels of pressurized water reactors (PWR). The utilization of certain amines, other than ammonia (morpholine and cyclohexylamine) may lead only to some limited improvements due to the thermal decomposition of the reagents and due to the subsequent effects they may have on the chemical characteristics of the water and on the condensate treatments. The solutions related to the chemistry modifications of the water in order to fight erosion-corrosion phenomena are in fact a palliative to conceptional errors which can be useful whenever it is impossible to do otherwise [fr

  6. Recommendations for erosion-corrosion allowance for Multi-Function Waste Tank Facility tanks

    International Nuclear Information System (INIS)

    Carlos, W.C.; Brehm, W.F.; Larrick, A.P.; Divine, J.R.

    1994-10-01

    The Multi-Function Waste Tank Facility carbon steel tanks will contain mixer pumps that circulate the waste. On the basis of flow characteristics of the system and data from the literature, an erosion allowance of 0.075 mm/y (3 mil/year) was recommended for the tank bottoms, in addition to the 0.025 mm/y (1 mil/year) general corrosion allowance

  7. The effect of the PWR secondary circuit water chemistry on erosion corrosion

    International Nuclear Information System (INIS)

    Kaplan, J.

    1993-07-01

    The secondary circuit of WWER-440 and WWER-1000 reactors is described. The causes of erosion corrosion are outlined, and the effects of the physical properties and chemical composition of water are discussed with emphasis on specific conductivity and concentrations of oxygen, ammonia, iron, sodium, silicon and organics. Described are corrective actions to eliminate the deviations from the normal state during reactor power reduction or reactor shutdown. (J.B.)

  8. Flow velocity effect on the corrosion/erosion in water injection systems

    International Nuclear Information System (INIS)

    Jimenez, C.; Mendez, J.

    1998-01-01

    The main causes of fails at water injection lines on the secondary petroleum recovery systems are related with corrosion/erosion problems which are influenced by the flow velocity, the presence of dissolved oxygen, solids in the medium and the microorganisms proliferation. So too, this corrosion process promotes the suspended solids generation which affects the water quality injected, causing wells tamponage and loss of injectivity, with the consequent decrease in the crude production. This situation has been impacted in meaning order at the production processes of an exploration enterprise which utilizes the Maracaibo lake as water resource for their injection by pattern projects. Stating that, it was developed a study for determining in experimental order the effect of flow velocity on the corrosion/erosion process joined to the presence of dissolved oxygen which allows to determine the optimum range of the said working velocity for the water injection systems. This range is defined by critical velocities of bio layers deposition and erosion. They were realized simulation pilot tests of the corrosion standard variables, concentration of dissolved oxygen and fluid velocity in the injection systems with filtered and non filtered water. For the development of these tests it was constructed a device which allows to install and expose cylindrical manometers of carbon steel according to predetermined conditions which was obtained the necessary information to make correlations the results of these variables. Additionally, they were determined the mathematical models that adjusts to dynamical behavior of the corrosion/erosion process, finding the optimum range of the flow velocity for the control of this process, being necessary to utilize the following techniques: Scanning Electron Microscopy (SEM), X-ray dispersion analysis (EDX) for encourage the surface studies. They were effected morphological analysis of the surfaces studies and the values were determined of

  9. The Effect of pH on Slurry Erosion-Corrosion of Tungsten Carbide Overlays Alloyed with Ru

    Science.gov (United States)

    Nelwalani, Ndivhuwo B.; van der Merwe, Josias W.

    2018-01-01

    The aim of the study was to determine the effect of Ru additions to WC-Fe overlays when exposed to low pH slurry erosion conditions. These overlays were applied through Plasma Transferred Arc, and the original bulk Ru powder concentrations varied from 0.5 to 5 wt.%. A slurry jet impingement erosion-corrosion test rig was used to evaluate wear, and electrochemical measurements were performed to characterize the corrosion properties. The slurry mixtures contained silica sand and synthetic mine water. The pH was varied between 3 and 6.5 for the slurry erosion tests and lowered further for the corrosion characterization. Samples were examined optically and with a scanning electron microscope using energy-dispersive x-ray spectroscopy. X-ray diffraction analysis was used to determine the phases present. For the slurry erosion-corrosion results at the pH of 6.5, addition of Ru did not show a decrease in erosion-corrosion rates. However, when the pH was decreased to 3, by the addition of HCl, Ru improved the resistance. From the electrochemistry, it was also clear that Ru additions improved the corrosion resistance, but more than 1 wt.% Ru was required. At very low pH levels, the presence of Ru was not able to prevent corrosion.

  10. The Effect of pH on Slurry Erosion-Corrosion of Tungsten Carbide Overlays Alloyed with Ru

    Science.gov (United States)

    Nelwalani, Ndivhuwo B.; van der Merwe, Josias W.

    2018-02-01

    The aim of the study was to determine the effect of Ru additions to WC-Fe overlays when exposed to low pH slurry erosion conditions. These overlays were applied through Plasma Transferred Arc, and the original bulk Ru powder concentrations varied from 0.5 to 5 wt.%. A slurry jet impingement erosion-corrosion test rig was used to evaluate wear, and electrochemical measurements were performed to characterize the corrosion properties. The slurry mixtures contained silica sand and synthetic mine water. The pH was varied between 3 and 6.5 for the slurry erosion tests and lowered further for the corrosion characterization. Samples were examined optically and with a scanning electron microscope using energy-dispersive x-ray spectroscopy. X-ray diffraction analysis was used to determine the phases present. For the slurry erosion-corrosion results at the pH of 6.5, addition of Ru did not show a decrease in erosion-corrosion rates. However, when the pH was decreased to 3, by the addition of HCl, Ru improved the resistance. From the electrochemistry, it was also clear that Ru additions improved the corrosion resistance, but more than 1 wt.% Ru was required. At very low pH levels, the presence of Ru was not able to prevent corrosion.

  11. Resistance of Silicon Nitride Turbine Components to Erosion and Hot Corrosion/oxidation Attack

    Science.gov (United States)

    Strangmen, Thomas E.; Fox, Dennis S.

    1994-01-01

    Silicon nitride turbine components are under intensive development by AlliedSignal to enable a new generation of higher power density auxiliary power systems. In order to be viable in the intended applications, silicon nitride turbine airfoils must be designed for survival in aggressive oxidizing combustion gas environments. Erosive and corrosive damage to ceramic airfoils from ingested sand and sea salt must be avoided. Recent engine test experience demonstrated that NT154 silicon nitride turbine vanes have exceptional resistance to sand erosion, relative to superalloys used in production engines. Similarly, NT154 silicon nitride has excellent resistance to oxidation in the temperature range of interest - up to 1400 C. Hot corrosion attack of superalloy gas turbine components is well documented. While hot corrosion from ingested sea salt will attack silicon nitride substantially less than the superalloys being replaced in initial engine applications, this degradation has the potential to limit component lives in advanced engine applications. Hot corrosion adversely affects the strength of silicon nitride in the 850 to 1300 C range. Since unacceptable reductions in strength must be rapidly identified and avoided, AlliedSignal and the NASA Lewis Research Center have pioneered the development of an environmental life prediction model for silicon nitride turbine components. Strength retention in flexure specimens following 1 to 3300 hour exposures to high temperature oxidation and hot corrosion has been measured and used to calibrate the life prediction model. Predicted component life is dependent upon engine design (stress, temperature, pressure, fuel/air ratio, gas velocity, and inlet air filtration), mission usage (fuel sulfur content, location (salt in air), and times at duty cycle power points), and material parameters. Preliminary analyses indicate that the hot corrosion resistance of NT154 silicon nitride is adequate for AlliedSignal's initial engine

  12. Slurry Erosion and Corrosion Behavior of Some Engineering Polymers Applied by Low-Pressure Flame Spray

    Science.gov (United States)

    Lima, Carlos Roberto Camello; Mojena, Miguel Angel Reyes; Rovere, Carlos Alberto Della; de Souza, Natalia Ferraresso Cardoso; Fals, Hipolito Domingo Carvajal

    2016-11-01

    The erosive wear and corrosion resistance of three types of flame spray-deposited polymer coatings was analyzed. The erosive wear test was performed in slurry pot tester with rotational movement using distilled water and mix quartz particles (300 g/l). Two impact angles of the particles were used, reaching 4.15 m/s average impact velocity. Corrosion resistance of the polymer coatings and degradation behavior were investigated by electrochemical impedance spectroscopy in a solution of 0.5 M sodium chloride at room temperature for a total immersion time of 1 year. The interpretation of the results was made according to the Bode plot. It is proven a better slurry erosion wear performance for PEEK and PA12 coatings when the particles impact at 90° angle. For impact angle of 30°, there is no significant difference in the erosion performance of PEEK, PEI, and PA12 coatings. No major changes occurred in the impedance module for PA12 and PEEK samples, indicating that these coatings can protect the steel substrate for extended periods of time. The lower PEI performance is believed to be related to the improper choice of spraying parameters, as the spray conditions were kept constant for the three feedstock materials.

  13. Evaluation of the susceptibility to pitting corrosion of structural steels, including steels with modified surface

    International Nuclear Information System (INIS)

    Lunarska, E.; Nikiforow, K.

    2001-01-01

    Although the low alloy ferrite-perlite and bainite-martensite steels mostly undergo the general corrosion, pitting corrosion occurring under certain conditions jeopardizes the safety of installations, causing perforation of walls or initiation of crack. On the basis of electrochemical, corrosion and microscopic examinations, the conditions simulating typical industrial corrosion environments, containing Cl - ions have been selected, to which the parts of machines, devices and installation are subjected. The test parameters provide the preferential pitting corrosion without prevailing general corrosion, and provide the similar type of corrosion of different kinds of ferrite-perlite and bainite-martensite steels, including steels with modified surface layer. The proposed express method allows to evaluate the susceptibility to pitting corrosion and to evaluate the effect of surface modification on susceptibility to pitting corrosion in environments containing Cl - ions. The method may be applied for the proper selection of materials exploited under pitting corrosion conditions and for preparation of precorroded samples for mechanical testing. (author)

  14. A Study on Cavitation Erosion Behaviors of Corrosion-resistance Thermal Spray Coating Materials

    International Nuclear Information System (INIS)

    Jin, Hee Seok

    2003-02-01

    The hydraulic machinery of screw propeller and pump impellers is damaged by cavitation erosion in sea water. The cavitation erosion is a phenomenon leading a functional disorder of various fluid machinery and dropping off in efficiency by cavity fluid fluctuation. This study is investigated the cavitation erosion of various metallic coatings made by thermal spraying methods. The coating materials are AMDRY625, Cr 2 O 3 , SUS316, Zn, Al. These metals are coated on substrate of high strength brass ( Cu - Zn ). Test specimens are immersed in 3.5% NaCl solution for 500 and 1000 hours, respectively. After pre-corrosion, the cavitation erosion test was conducted on coating specimens in 3.5% NaCl solution along 210 minutes. The results are summarized as follows : 1. Both substrate and test specimens coated by thermal spray underwent weight loss in proportion to the time length of the cavitation erosion test, and the weight loss happened more to 1,000 hour-immersed test specimens and 500 hour-immersed ones in the time order rather than the ones in non-corrosion condition. 2. Substrate and Amdry625 and SUS316 test specimens were all influenced very little by weight loss regardless of the time length and the conditions of the test. 3. The amount of weight loss of aluminum and zinc test specimens and Cr 2 O 3 test specimens heavily increased at the early stage regardless of the conditions but later decreased after the coated layers were fretted by cavitation erosion. 4. The comparison of weight loss after the test showed that Amdry625, SUS316 and substrate underwent very little weight loss, proving to be the very likely materials to bear cavitation erosion but aluminum and zinc and Cr 2 O 3 underwent very great weight loss, proving to be the very unlikely materials to bear cavitation erosion. 5. After the test, the surfaces of Amdry625, SUS316 and substrate showed that they had been less damaged by cavitation erosion but the rest showed that they had been very much damaged by

  15. The erosion/corrosion of small superalloy turbine rotors operating in the effluent of a PFB coal combustor

    Science.gov (United States)

    Zellars, G. R.; Benford, S. M.; Rowe, A. P.; Lowell, C. E.

    1979-01-01

    The operation of a turbine in the effluent of a pressurized fluidized bed (PFB) coal combustor presents serious materials problems. Synergistic erosion/corrosion and deposition/corrosion interactions may favor the growth of erosion-resistant oxides on blade surfaces, but brittle cracking of these oxides may be an important source of damage along heavy particle paths. Integrally cast alloy 713LC and IN792 + Hf superalloy turbine rotors in a single-stage turbine with 6% partial admittance have been operated in the effluent of a PFB coal combustor for up to 164 hr. The rotor erosion pattern exhibits heavy particle separation with severe erosion at the leading edge, pressure side center, and suction side trailing edge at the tip. The erosion distribution pattern gives a spectrum of erosion/oxidation/deposition as a function of blade position. The data suggest that preferential degradation paths may exist even under the targeted lower loadings (less than 20 ppm).

  16. Effects of Rare Earth Metal addition on the cavitation erosion-corrosion resistance of super duplex stainless steels

    Science.gov (United States)

    Shim, Sung-Ik; Park, Yong-Soo; Kim, Soon-Tae; Song, Chi-Bok

    2002-05-01

    Austenitic stainless steels such as AISI 316L have been used in equipment in which fluid flows at high speeds which can induce cavitation erosion on metallic surfaces due to the collapse of cavities, where the collapse is caused by the sudden change of local pressure within the liquid. Usually AISI 316L is susceptible to cavitation erosion. This research focuses on developing a better material to replace the AISI 316L used in equipment with high speed fluid flow, such as impellers. The effects of Rare Earth Metal (REM) additions on the cavitation erosion-corrosion resistance of duplex stainless steels were studied using metallographic examination, the potentiodynamic anodic polarization test, the tensile test, the X-ray diffraction test and the ultrasonic cavitation erosion test. The experimental alloys were found to have superior mechanical properties due to interstitial solid solution strengthening, by adding high nitrogen (0.4%), as well as by the refinement of phases and grains induced by fine REM oxides and oxy-sulfides. Corrosion resistance decreases in a gentle gradient as the REM content increases. However, REM containing alloys show superior corrosion resistance compared with that of other commercial alloys (SAF 2507, AISI 316L). Owing to their excellent mechanical properties and corrosion resistance, the alloys containing REM have high cavitation erosion-corrosion resistance.

  17. Predicting Effects of Corrosion Erosion of High Strength Steel Pipelines Elbow on CO2-Acetic Acid (HAc) Solution

    Science.gov (United States)

    Asmara, Y. P.; Ismail, M. F.; Giok Chui, L.; Halimi, Jamiludin

    2016-02-01

    Simultaneously effect of erosion combined with corrosion becomes the most concern in oil and gas industries. It is due to the fast deterioration of metal as effects of solid particles mixed with corrosive environment. There are many corrosion software to investigate possible degradation mechanisms developed by researchers. They are using many combination factors of chemical reactions and physical process. However effects of CO2 and acid on pipelines orientations are still remain uncovered in their simulation. This research will investigate combination effects of CO2 and HAc on corrosion and erosion artificial environmental containing sands particles in 45°, 90° and 180° elbow pipelines. The research used theoretical calculations combined with experiments for verification. The main concerns are to investigate the maximum erosion corrosion rate and maximum shear stress at the surface. Methodology used to calculate corrosion rate are Linear Polarization Resistance (LPR) and weight loss. The results showed that at 45°, erosion rate is the more significant effects in contributing degradation of the metal. The effects of CO2 and HAc gave significant effects when flow rate of the solution are high which reflect synergism effects of solid particles and those chemical compositions.

  18. Probabilistic methods for evaluation of erosion-corrosion wall thinning in french pressurized water reactors

    International Nuclear Information System (INIS)

    Ardillon, E.; Bouchacourt, M.

    1994-04-01

    This paper describes the application of the probabilistic approach to a selected study section having known characteristics. The method is based on the physico-chemical model of erosion-corrosion, the variables of which are probabilized. The three main aspects of the model, namely the thermohydraulic flow conditions, the chemistry of the fluid, and the geometry of the installation, are described. The study ultimately makes it possible determine: - the evolution of wall thinning distribution, using the power station's measurements; - the main parameters of influence on the kinetics of wall thinning; - the evolution of the fracture probabilistic of the pipe in question. (authors). 10 figs., 7 refs

  19. Electrochemical noise of the erosion-corrosion of copper in relation with its hydrodynamic parameters; Ruido electroquimico de la erosion-corrosion en cobre: su relacion con los parametros hidrodinamicos

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda, I.; Romero, M.; Malo, J.M.; Uruchurtu, J.

    2010-07-01

    This work presents the electrochemical noise results obtained of the surface degradation on copper, due to erosion corrosion phenomena, which were a function of the hydrodynamic parameters of the system (fluid movement). A modified rotating cylinder (RC) comprising three ring electrodes under two rotating speeds (880 and 1750 rpm with a Reynolds numbers 1486 Re and 2972 Re, respectively) were used. Characteristic electrochemical noise spectra as a function of the hydrodynamic parameters were found, as well as surface attack intensities the noise signal. An increase and a more uniform attack due to particle impact was related to larger particle size and lesser erosion corrosion intensity, in the form of more localized attack over the surface, was obtained for smaller ones. Erosion corrosion attack presents characteristic electrochemical current and potential noise signals, according to the laminar or transitional turbulent regime and particle size added. (Author).

  20. Thin Layer Activation (TLA) Technique Application for Monitoring Corrosion, Erosion and Wear on Industrial Components

    International Nuclear Information System (INIS)

    Hari Suryanto; Sunarhadijoso Soenarjo; Imam Kambali

    2003-01-01

    Thin Layer Activation (TLA) technique is one of high-precision and effective nuclear methods for measurement and monitoring corrosion, erosion and wear on industrial components. This technique was developed by using low current charged particle beam produced from a cyclotron to activate a surface layer of component. In this case only the surface layer in the μm range at the desired parts of the component are activated. The surface activation lets a very low radioactivity concerning to safety aspect but still can be detected and measured well due to specificity and sensitivity of nuclear reaction produced. Some reported experiences on TLA technique have confirmed that the technique is proper fully recommended to be applied in various industries such as automotive, petrochemical, petroleum, power plant, transportation, lubricant oil etc. The measurement and monitoring of corrosion, erosion and wear rates can be remotely and continuously performed, on-line and in-situ, giving a real-time information. By giving a real-time information, TLA technique provides a considerably better estimation of the components lifetimes for any operating condition. The measurement sensitivity of surface loss rate by using this method can reach up to 0.01 μm depends on the type of applications. The application of the TLA technique lets early observation on the damage of the system preventing any disturbance on industrial process, either in the form of accident during the process or that of unscheduled interruption. (author)

  1. Liquid metal corrosion/erosion investigations of structure materials in lead cooled systems: Part 1

    Science.gov (United States)

    Kieser, M.; Muscher, H.; Weisenburger, A.; Heinzel, A.; Müller, G.

    2009-08-01

    In future lead cooled nuclear power systems the heavy liquid-metal pump will be placed in the hot temperature region of the reactor. This combines corrosion problematic at elevated temperatures with erosion at the impeller of the pump. Several steels designed for conventional mechanical high loaded pumps and the SiSiC have been tested in oxygen containing stagnant lead (10 -6 and 10 -8 wt%) at 550 and 600 °C for 2000 and 4000 h in the COSTA-facilities. Only SiSiC shows no influence by the liquid metal. No dissolution attack occurs at cast iron steels but inner oxidation takes place. NORILOY shows no dissolution attack. All other steels are attacked by liquid lead at one of the conditions. To evaluate the erosion-corrosion attack a new test facility allowing velocities of the lead of up to 20 m/s was designed and constructed. With a CFD-code the behaviour and flow velocity of the lead are simulated.

  2. A mathematical model for erosion-corrosion downstream of an orifice

    International Nuclear Information System (INIS)

    Thomas, R.M.

    1989-08-01

    In certain types of nuclear plant, the internal surfaces of the steel high-pressure boiler tubes become covered with magnetite. This normal growth of protective magnetite may, in unfavourable circumstances, be replaced by rapid attack on the tube wall. Particularly at risk are the regions downstream of the orifice plates commonly fitted near the boiler inlet. An attempt is made to construct a mathematical model for this erosion-corrosion which is considerably more complete than those available hitherto. A systematic synthesis is developed of the various aspects of the phenomenon, namely the mechanism of the topotactic oxidation at the interface between magnetite and metal, the kinetics of the electrode reactions at the magnetite/solution interface, the thermodynamics of magnetite solubility and the calculation of mass transfer in solution. With one choice of parameters and some simplification, the treatment reduces to the original theory of Bignold. (author)

  3. Method and device for the determination of material loss due to corrosion and/or erosion

    International Nuclear Information System (INIS)

    Dugstad, A.; Videm, K.

    1990-01-01

    The invention relates to a method and an apparatus for gauging material loss due to corrosion and/or erosion during a certain period of time from a given piece of material which previously has been made radioactive. The material loss is determined by measuring the intensity of the radiactive radiation from the material by means of a radiation intensity meter disposed at a measuring site a fixed distance from said piece of material for the measurement of the radioactive radiation from the piece both at the beginning and at the end of said period of time. Each of the measurements is calibrated by means of an additional radiation source disposed for controllably adopting either a most radiation screened position or alternatively a least screened position with respect to a radiation screen, and thereby providing a known radiation intensity at the measuring site in both positions. The least radiation screened position provides full unscreened radiation intensity at the measuring site, whereas the most screened position provides negligible radiation intensity at said site. The measurement results in the two positions are subsequently compared in order to deduce the contribution of said piece of material to the combined radiation intensity in proporsion to the known contribution of the radiation source. The additional radiation source is preferable made from a calibration body composed of the same material as the piece of material exposed to corrosion and/or erosion, the calibration body body being activated at the same time and by the same activation process as said piece. The calibration body is preferably dimensioned to provide at all time the same radiation intensity at the measuring site as a predetermined material loss from the piece of material, e.g. a prefixed thickness reduction of the same. 4 figs

  4. Corrosion of PWR steam generators

    International Nuclear Information System (INIS)

    Garnsey, R.

    1979-01-01

    Some designs of pressurized water reactor (PWR) steam generators have experienced a variety of corrosion problems which include stress corrosion cracking, tube thinning, pitting, fatigue, erosion-corrosion and support plate corrosion resulting in 'denting'. Large international research programmes have been mounted to investigate the phenomena. The operational experience is reviewed and mechanisms which have been proposed to explain the corrosion damage are presented. The implications for design development and for boiler and feedwater control are discussed. (author)

  5. Flow velocity effect on the corrosion/erosion in water injection systems; Efecto de la velocidad de flujo en la corrosion/erosion en sistemas de inyeccion de agua

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez, C.; Mendez, J. [PDVSA Exploracion y reduccion, Departamento de Ingenieria de Instalaciones, Torres Petroleras EX-MRV, Torre Lama, Piso No. 6, Zulia, Apartado 4013, Venezuela (Venezuela)

    1998-12-31

    The main causes of fails at water injection lines on the secondary petroleum recovery systems are related with corrosion/erosion problems which are influenced by the flow velocity, the presence of dissolved oxygen, solids in the medium and the microorganisms proliferation. So too, this corrosion process promotes the suspended solids generation which affects the water quality injected, causing wells tamponage and loss of injectivity, with the consequent decrease in the crude production. This situation has been impacted in meaning order at the production processes of an exploration enterprise which utilizes the Maracaibo lake as water resource for their injection by pattern projects. Stating that, it was developed a study for determining in experimental order the effect of flow velocity on the corrosion/erosion process joined to the presence of dissolved oxygen which allows to determine the optimum range of the said working velocity for the water injection systems. This range is defined by critical velocities of bio layers deposition and erosion. They were realized simulation pilot tests of the corrosion standard variables, concentration of dissolved oxygen and fluid velocity in the injection systems with filtered and non filtered water. For the development of these tests it was constructed a device which allows to install and expose cylindrical manometers of carbon steel according to predetermined conditions which was obtained the necessary information to make correlations the results of these variables. Additionally, they were determined the mathematical models that adjusts to dynamical behavior of the corrosion/erosion process, finding the optimum range of the flow velocity for the control of this process, being necessary to utilize the following techniques: Scanning Electron Microscopy (SEM), X-ray dispersion analysis (EDX) for encourage the surface studies. They were effected morphological analysis of the surfaces studies and the values were determined of

  6. Ultrasonic monitoring of erosion/corrosion thinning rates in industrial piping systems.

    Science.gov (United States)

    Honarvar, Farhang; Salehi, Farzaneh; Safavi, Vahid; Mokhtari, Arman; Sinclair, Anthony N

    2013-09-01

    Monitoring pipe wall erosion/corrosion thinning rates is an important issue in petrochemical and power generation industries. In this paper, two signal processing techniques are utilized for estimating the thinning rate based on ultrasonic pipe wall thickness data collected over a short period of time. The first is a combination of cross-correlation and polynomial curve fitting and the second is a model-based estimation (MBE) scheme. These techniques are applied to data collected from an accelerated thinning rate apparatus and both show that they are capable of estimating the thinning rates quickly in short time periods with good accuracy. In laboratory applications, thinning rates as low as 10 μm/year were measured within 15 days with an uncertainty of ±1.5 μm/year by both techniques. Although the MBE technique can yield marginally better accuracy, the greater stability and computational speed of the cross-correlation technique make it the preferred choice for industrial use. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Preliminary review of mass transfer and flow visualization studies and techniques relevant to the study of erosion-corrosion of reactor piping systems

    Energy Technology Data Exchange (ETDEWEB)

    Kuzay, T.M.; Halle, H.J.; Kasza, K.E.

    1988-06-01

    This report provides some background information on the failed piping at the Surry-2 reactor; a summary of pertinent literature on mass transfer in related geometries; and a description of methodologies for visualization and erosion rate measurements in laboratory model studies that can provide greater insight into the role of flow geometry in erosion-corrosion. 18 refs., 9 figs., 1 tab.

  8. Preliminary review of mass transfer and flow visualization studies and techniques relevant to the study of erosion-corrosion of reactor piping systems

    International Nuclear Information System (INIS)

    Kuzay, T.M.; Halle, H.J.; Kasza, K.E.

    1988-06-01

    This report provides some background information on the failed piping at the Surry-2 reactor; a summary of pertinent literature on mass transfer in related geometries; and a description of methodologies for visualization and erosion rate measurements in laboratory model studies that can provide greater insight into the role of flow geometry in erosion-corrosion. 18 refs., 9 figs., 1 tab

  9. Flow Accelerated Erosion-Corrosion (FAC) considerations for secondary side piping in the AP1000R nuclear power plant design

    International Nuclear Information System (INIS)

    Vanderhoff, J. F.; Rao, G. V.; Stein, A.

    2012-01-01

    The issue of Flow Accelerated Erosion-Corrosion (FAC) in power plant piping is a known phenomenon that has resulted in material replacements and plant accidents in operating power plants. Therefore, it is important for FAC resistance to be considered in the design of new nuclear power plants. This paper describes the design considerations related to FAC that were used to develop a safe and robust AP1000 R plant secondary side piping design. The primary FAC influencing factors include: - Fluid Temperature - Pipe Geometry/layout - Fluid Chemistry - Fluid Velocity - Pipe Material Composition - Moisture Content (in steam lines) Due to the unknowns related to the relative impact of the influencing factors and the complexities of the interactions between these factors, it is difficult to accurately predict the expected wear rate in a given piping segment in a new plant. This paper provides: - a description of FAC and the factors that influence the FAC degradation rate, - an assessment of the level of FAC resistance of AP1000 R secondary side system piping, - an explanation of options to increase FAC resistance and associated benefits/cost, - discussion of development of a tool for predicting FAC degradation rate in new nuclear power plants. (authors)

  10. Kinetics of the σ Phase Precipitation in Respect of Erosion-corrosion Wear of Duplex Cast Steel

    Directory of Open Access Journals (Sweden)

    Brodziak-Hyska A.

    2014-03-01

    Full Text Available The examined material comprised two grades of corrosion-resistant cast steel, namely GX2CrNiMoN25-6-3 and GX2CrNiMoCuN25-6-3- 3, used for example in elements of systems of wet flue gas desulphurisation in power industry. The operating conditions in media heated up to 70°C and containing Cl' and SO4 ions and solid particles produce high erosive and corrosive wear.The work proposes an application of the σ phase as a component of precipitation strengthening mechanism in order to increase the functional properties of the material. The paper presents the results of examination of the kinetics of σ phase precipitation at a temperature of 800°C and at times ranging from 30 to 180 minutes. Changes in the morphology of precipitates of the σ phase were determined using the value of shape factor R. Resistance to erosion-corrosion wear of duplex cast steel was correlated with the kinetics of sigma phase precipitating.

  11. Study of corrosion-erosion behaviour of stainless alloys in industrial phosphoric acid medium

    International Nuclear Information System (INIS)

    Guenbour, Abdellah; Hajji, Mohamed-Adil; Jallouli, El Miloudi; Bachir, Ali Ben

    2006-01-01

    The corrosion and corrosion-abrasion resistance of some stainless steels in industrial phosphoric acid 30% P 2 O 5 has been studied using electrochemical techniques. The corrosion rate of materials increases with the increase of temperature. Alloys which contain chromium, molybdenum and nitrogen in sufficient quantities present the best behaviour. In the abrasion-corrosion conditions, the experimental device set up allowed to follow continually samples electrochemical behaviour. Under dynamic conditions and without solid particles, the increase of acid projection speed has no effect on the alloys corrosion behaviour. The adding of abrasive leads to a general increase of corrosion rate and to a decrease of material resistance. Under these conditions, materials attack is controlled by synergistic effect between the abrasion and the impurities. The cast 30% Cr shows good resistance according to his high chromium content

  12. Organo-Aluminate Polymeric Materials as Advanced Erosion/Corrosion Resistant Thin Film Coatings

    National Research Council Canada - National Science Library

    Cook, Ronald

    1997-01-01

    ...) and hazardous air pollutants (HAPs). The coating system is based on the development of carboxylato- alumoxane precursors for fabrication of corrosion resistant oxide barrier layers and alumoxane-epoxy based primer coats...

  13. Coatings on X20Cr13 and X10CrNiMoV 1222 compressor blades as a protection against erosion and corrosion fatigue

    International Nuclear Information System (INIS)

    Schmitt-Thomas, K.G.

    1989-01-01

    Compressor bladings of stationary gas turbines and aircraft engines are very often covered with an anti-corrosive coating in order to prevent the failure of the blades due to corrosion fatigue. This study tested inorganically bound aluminium coatings - consisting of aluminium pigments which are intercalated in a matrix of chromate/phosphate compounds - with regard to their suitability as compressor blade coatings. In addition to the determination of the fundamental knowledge on their behaviour as regards erosion, corrosion and corrosion fatigue in an undamaged state, corrosion and corrosion fatigue studies were carried out on coating systems which were damaged due to blasting wear. Industrially produced aluminium coatings were taken into account which promised a high degree of resistance to corrosion and erosion, and which are a representative cross section of the possible constellations of coating parameters. Comparative studies were carried out on aluminium diffusion layers, electrolytically precipitated aluminium layers and on modified, inorganically bound aluminium coatings (with additional TiN surface layer). (orig./MM) [de

  14. Water Chemistry and Clad Corrosion/Deposition Including Fuel Failures. Proceedings of a Technical Meeting

    International Nuclear Information System (INIS)

    2013-03-01

    Corrosion is a principal life limiting degradation mechanism in nuclear steam supply systems, particularly taking into account the trends in increasing fuel burnup, thermal ratings and cycle length. Further, many plants have been operating with varying water chemistry regimes for many years, and issues of crud (deposition of corrosion products on other surfaces in the primary coolant circuit) are of significant concern for operators. At the meeting of the Technical Working Group on Fuel Performance and Technology (TWGFPT) in 2007, it was recommended that a technical meeting be held on the subject of water chemistry and clad corrosion and deposition, including the potential consequences for fuel failures. This proposal was supported by both the Technical Working Group on Advanced Technologies for Light Water Reactors (TWG-LWR) and the Technical Working Group on Advanced Technologies for Heavy Water Reactors (TWG-HWR), with a recommendation to hold the meeting at the National Nuclear Energy Generating Company ENERGOATOM, Ukraine. This technical meeting was part of the IAEA activities on water chemistry, which have included a series of coordinated research projects, the most recent of which, Optimisation of Water Chemistry to Ensure Reliable Water Reactor Fuel Performance at High Burnup and in Ageing Plant (FUWAC) (IAEATECDOC-1666), concluded in 2010. Previous technical meetings were held in Cadarache, France (1985), Portland, Oregon, USA (1989), Rez, Czech Republic (1993), and Hluboka nad Vltavou, Czech Republic (1998). This meeting focused on issues associated with the corrosion of fuel cladding and the deposition of corrosion products from the primary circuit onto the fuel assembly, which can cause overheating and cladding failure or lead to unplanned power shifts due to boron deposition in the clad deposits. Crud deposition on other surfaces increases radiation fields and operator dose and the meeting considered ways to minimize the generation of crud to avoid

  15. A study on the corrosion and erosion behavior of electroless nickel and TiAlN/ZrN duplex coatings on ductile iron

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chung-Kwei [School of Dental Technology, Taipei Medical University, Taipei 110, Taiwan (China); Hsu, Cheng-Hsun, E-mail: chhsu@ttu.edu.tw [Department of Materials Engineering, Tatung University, Taipei 104, Taiwan (China); College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Cheng, Yin-Hwa [Department of Materials Engineering, Tatung University, Taipei 104, Taiwan (China); Ou, Keng-Liang [College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Department of Mechanical Engineering, National Central University, Taoyuan 320, Taiwan (China); Lee, Sheng-Long [Research Center for Biomedical Devices and Prototyping Production, Taipei Medical University, Taipei 110, Taiwan (China)

    2015-01-01

    Highlights: • Electroless nickel was used as an interlayer for TiAlZrN-coated ductile iron. • The duplex coatings evidently improved corrosion resistance of ductile iron. • The duplex coated ductile iron showed a good erosion resistance. - Abstract: This study utilized electroless nickel (EN) and cathodic arc evaporation (CAE) technologies to deposit protective coatings onto ductile iron. Polarization corrosion tests were performed in 3.5 wt.% sodium chloride, and also erosion tests were carried out by using Al{sub 2}O{sub 3} particles (∼177 μm in size and Mohr 7 scale) of about 5 g. Surface morphologies of the corroded and eroded specimens were observed separately. To further understand the coating effects on both the corrosive and erosive behavior of ductile iron, coating structure, morphology, and adhesion were analyzed using X-ray diffractormeter, scanning electron microscopy, and Rockwell-C indenter, respectively. The results showed that the EN exhibited an amorphous structure while the CAE-TiAlN/ZrN coating was a multilayered nanocrystalline. When the TiAlN/ZrN coated specimen with EN interlayer could effectively increase the adhesion strength between the CAE coating and substrate. Consequently, the combination of TiAlN/ZrN and EN delivered a better performance than did the monolithic EN or TiAlN/ZrN for both corrosion and erosion protection.

  16. A study on the corrosion and erosion behavior of electroless nickel and TiAlN/ZrN duplex coatings on ductile iron

    International Nuclear Information System (INIS)

    Lin, Chung-Kwei; Hsu, Cheng-Hsun; Cheng, Yin-Hwa; Ou, Keng-Liang; Lee, Sheng-Long

    2015-01-01

    Highlights: • Electroless nickel was used as an interlayer for TiAlZrN-coated ductile iron. • The duplex coatings evidently improved corrosion resistance of ductile iron. • The duplex coated ductile iron showed a good erosion resistance. - Abstract: This study utilized electroless nickel (EN) and cathodic arc evaporation (CAE) technologies to deposit protective coatings onto ductile iron. Polarization corrosion tests were performed in 3.5 wt.% sodium chloride, and also erosion tests were carried out by using Al 2 O 3 particles (∼177 μm in size and Mohr 7 scale) of about 5 g. Surface morphologies of the corroded and eroded specimens were observed separately. To further understand the coating effects on both the corrosive and erosive behavior of ductile iron, coating structure, morphology, and adhesion were analyzed using X-ray diffractormeter, scanning electron microscopy, and Rockwell-C indenter, respectively. The results showed that the EN exhibited an amorphous structure while the CAE-TiAlN/ZrN coating was a multilayered nanocrystalline. When the TiAlN/ZrN coated specimen with EN interlayer could effectively increase the adhesion strength between the CAE coating and substrate. Consequently, the combination of TiAlN/ZrN and EN delivered a better performance than did the monolithic EN or TiAlN/ZrN for both corrosion and erosion protection

  17. Final Report For The Erosion And Corrosion Analysis Of Waste Transfer Primary Pipeline Sections From 241-SY Tank Farm

    Energy Technology Data Exchange (ETDEWEB)

    Page, J. S.; Wyrwas, R. B.; Cooke, G. A.

    2012-10-04

    Three sections of primary transfer pipeline removed from the 241-SY Tank Farm in Hanford's 200 West area, labeled as SN-285, SN-286, and SN-278, were analyzed for the presence and amount of corrosion and erosion on the inside surface of the transfer pipe. All three sections of pipe, ranging in length between 6 and 8 in., were received at the 222-S Laboratory still in the pipe-in-pipe assembly. The annular spaces were filled with urethane foam injected into the pipes for as low as reasonably achievable (ALARA) purposes. The 3-in. primary transfer pipes were first separated from the outer encasement, 6-in. pipes. The pipes were cut into small sections, or coupons, based upon the results of a non-destructive pipe wall thickness measurement which used an ultrasonic transducer. Following removal of the foam, the coupons were subjected to a series of analytical methods utilizing both optical microscopy and scanning electron microscopy to obtain erosion and corrosion information. The ultrasonic transducer analysis of the SN-285 primary pipe did not show any thinned locations in the pipe wall which were outside the expected range for the 3-in. schedule 40 pipe of 216 mils. A coupon was cut from the thinnest area on the pipe, and analysis of the inside surface, which was in contact with the tank waste, revealed a continuous layer of corrosion ~ 100 11m (4 mils) thick under a semi-continuous layer of tank waste residue ~ 20 11m (1 mil) thick. This residue layer was composed of an amorphous phase rich in chromium, magnesium, calcium, and chlorine. Small pits were detected throughout the inside pipe surface with depths up to ~ 50 11m (2 mils). Similarly, the SN-286 primary pipe did not show, by the ultrasonic transducer measurements, any thinned locations in the pipe wall which were outside the expected range for this pipe. Analysis of the coupon cut from the pipe section showed the presence of a tank waste layer containing sodium aluminate and phases rich in iron, calcium

  18. Final Report For The Erosion And Corrosion Analysis Of Waste Transfer Primary Pipeline Sections From 241-SY Tank Farm

    International Nuclear Information System (INIS)

    Page, J. S.; Wyrwas, R. B.; Cooke, G. A.

    2012-01-01

    Three sections of primary transfer pipeline removed from the 241-SY Tank Farm in Hanford's 200 West area, labeled as SN-285, SN-286, and SN-278, were analyzed for the presence and amount of corrosion and erosion on the inside surface of the transfer pipe. All three sections of pipe, ranging in length between 6 and 8 in., were received at the 222-S Laboratory still in the pipe-in-pipe assembly. The annular spaces were filled with urethane foam injected into the pipes for as low as reasonably achievable (ALARA) purposes. The 3-in. primary transfer pipes were first separated from the outer encasement, 6-in. pipes. The pipes were cut into small sections, or coupons, based upon the results of a non-destructive pipe wall thickness measurement which used an ultrasonic transducer. Following removal of the foam, the coupons were subjected to a series of analytical methods utilizing both optical microscopy and scanning electron microscopy to obtain erosion and corrosion information. The ultrasonic transducer analysis of the SN-285 primary pipe did not show any thinned locations in the pipe wall which were outside the expected range for the 3-in. schedule 40 pipe of 216 mils. A coupon was cut from the thinnest area on the pipe, and analysis of the inside surface, which was in contact with the tank waste, revealed a continuous layer of corrosion ∼ 100 11m (4 mils) thick under a semi-continuous layer of tank waste residue ∼ 20 11m (1 mil) thick. This residue layer was composed of an amorphous phase rich in chromium, magnesium, calcium, and chlorine. Small pits were detected throughout the inside pipe surface with depths up to ∼ 50 11m (2 mils). Similarly, the SN-286 primary pipe did not show, by the ultrasonic transducer measurements, any thinned locations in the pipe wall which were outside the expected range for this pipe. Analysis of the coupon cut from the pipe section showed the presence of a tank waste layer containing sodium aluminate and phases rich in iron

  19. Distributed soil loss estimation system including ephemeral gully development and tillage erosion

    Directory of Open Access Journals (Sweden)

    D. A. N. Vieira

    2015-03-01

    Full Text Available A new modelling system is being developed to provide spatially-distributed runoff and soil erosion predictions for conservation planning that integrates the 2D grid-based variant of the Revised Universal Soil Loss Equation, version 2 model (RUSLER, the Ephemeral Gully Erosion Estimator (EphGEE, and the Tillage Erosion and Landscape Evolution Model (TELEM. Digital representations of the area of interest (field, farm or entire watershed are created using high-resolution topography and data retrieved from established databases of soil properties, climate, and agricultural operations. The system utilizes a library of processing tools (LibRaster to deduce surface drainage from topography, determine the location of potential ephemeral gullies, and subdivide the study area into catchments for calculations of runoff and sheet-and-rill erosion using RUSLER. EphGEE computes gully evolution based on local soil erodibility and flow and sediment transport conditions. Annual tillage-induced morphological changes are computed separately by TELEM.

  20. Corrosion problems and solutions in oil refining and petrochemical industry

    CERN Document Server

    Groysman, Alec

    2017-01-01

    This book addresses corrosion problems and their solutions at facilities in the oil refining and petrochemical industry, including cooling water and boiler feed water units. Further, it describes and analyzes corrosion control actions, corrosion monitoring, and corrosion management. Corrosion problems are a perennial issue in the oil refining and petrochemical industry, as they lead to a deterioration of the functional properties of metallic equipment and harm the environment – both of which need to be protected for the sake of current and future generations. Accordingly, this book examines and analyzes typical and atypical corrosion failure cases and their prevention at refineries and petrochemical facilities, including problems with: pipelines, tanks, furnaces, distillation columns, absorbers, heat exchangers, and pumps. In addition, it describes naphthenic acid corrosion, stress corrosion cracking, hydrogen damages, sulfidic corrosion, microbiologically induced corrosion, erosion-corrosion, and corrosion...

  1. Cermet composite thermal spray coatings for erosion and corrosion protection in combustion environments of advanced coal-fired boilers. Semiannual technical report, January 14, 1997--August 14, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Schorr, B.S.; Levin, B.F.; DuPont, J.N.; Marder, A.R.

    1997-08-31

    Research is presently being conducted to determine the optimum ceramic/metal combination in thermally sprayed metal matrix composite coatings for erosion and corrosion resistance in new coal-fired boilers. The research will be accomplished by producing model cermet composites using powder metallurgy and electrodeposition methods in which the effect of ceramic/metal combination for the erosion and corrosion resistance will be determined. These results will provide the basis for determining the optimum hard phase constituent size and volume percent in thermal spray coatings. Thermal spray coatings will be applied by our industrial sponsor and tested in our erosion and corrosion laboratories. Bulk powder processed Ni-Al{sub 2}O{sub 3} composites were produced at Idaho National Engineering Laboratory. The composite samples contained 0, 21, 27, 37, and 45 volume percent Al{sub 2}O{sub 3} with an average particle size of 12 um. Also, to deposit model Ni-Al{sub 2}O{sub 3} coatings, an electrodeposition technique was developed and coatings with various volume fractions (0-35%) of Al{sub 2}O{sub 3} were produced. The powder and electrodeposition processing of Ni-Al{sub 2}O{sub 3} Composites provide the ability to produce two phase microstructure without changing the microstructure of the matrix material. Therefore, the effect of hard second phase particles size and volume fraction on erosion resistance could be analyzed.

  2. Recognition and Analysis of Corrosion Failure Mechanisms

    Directory of Open Access Journals (Sweden)

    Steven Suess

    2006-02-01

    Full Text Available Corrosion has a vast impact on the global and domestic economy, and currently incurs losses of nearly $300 billion annually to the U.S. economy alone. Because of the huge impact of corrosion, it is imperative to have a systematic approach to recognizing and mitigating corrosion problems as soon as possible after they become apparent. A proper failure analysis includes collection of pertinent background data and service history, followed by visual inspection, photographic documentation, material evaluation, data review and conclusion procurement. In analyzing corrosion failures, one must recognize the wide range of common corrosion mechanisms. The features of any corrosion failure give strong clues as to the most likely cause of the corrosion. This article details a proven approach to properly determining the root cause of a failure, and includes pictographic illustrations of the most common corrosion mechanisms, including general corrosion, pitting, galvanic corrosion, dealloying, crevice corrosion, microbiologically-influenced corrosion (MIC, corrosion fatigue, stress corrosion cracking (SCC, intergranular corrosion, fretting, erosion corrosion and hydrogen damage.

  3. Influence of chemical and materials in the rate of erosion corrosion. Modelling the cycle chemistry and materials characterization measurements on CN Cofrentes; Influencia de la quimica y materiales en la tasa de erosion corrosion. Modelizacion de la quimica del ciclo y medidas de caracterizacion de materiales en C. N. Cofrentes

    Energy Technology Data Exchange (ETDEWEB)

    Paule Ramos, A.; Sanchez-Zapata, J. D.

    2012-07-01

    The chemical cycle and the type of material are some of the factors that have great influence on the phenomenon of erosion-corrosion. The paper present the modeling of chemistry through the software cycle strategies COMSY and materials characterization measures undertaken in order to more effectively control this phenomenon in CN Cofrentes.

  4. A CFD-Based Study of the Feasibility of Adapting an Erosion Burner Rig for Examining the Effect of CMAS Deposition Corrosion on Environmental Barrier Coatings

    Science.gov (United States)

    Miller, Robert A.; Kuczmarski, Maria A.

    2015-01-01

    Thermodynamic and computational fluid dynamics modeling has been conducted to examine the feasibility of adapting the NASA-Glenn erosion burner rigs for use in studies of corrosion of environmental barrier coatings by the deposition of molten CMAS. The effect of burner temperature, Mach number, particle preheat, duct heating, particle size, and particle phase (crystalline vs. glass) were analyzed. Detailed strategies for achieving complete melting of CMAS particles were developed, thereby greatly improving the probability of future successful experimental outcomes.

  5. Influence of the nitrogen gas addition in the Ar shielding gas on the erosion-corrosion of tube-to-tube sheet welds of hyper duplex stainless steel

    International Nuclear Information System (INIS)

    Kim, Hye-Jin; Jeon, Soon-Hyeok; Kim, Soon-Tae; Lee, In-Sung; Park, Yong-Soo

    2014-01-01

    Duplex stainless steels with nearly equal fraction of the ferrite(α) phase and austenite(γ) phase have been increasingly used for various applications such as power plants, desalination facilities due to their high resistance to corrosion, good weldability, and excellent mechanical properties. Hyper duplex stainless steel (HDSS) is defined as the future duplex stainless steel with a pitting resistance equivalent (PRE= wt.%Cr+3.3(wt.%Mo+0.5wt.%W)+30wt.%N) of above 50. However, when HDSS is welded with gas tungsten arc (GTA), incorporation of nitrogen in the Ar shielding gas are very important because the volume fraction of α-phase and γ-phase is changed and harmful secondary phases can be formed in the welded zone. In other words, the balance of corrosion resistance between two phases and reduction of Cr 2 N are the key points of this study. The primary results of this study are as follows. The addition of N 2 to the Ar shielding gas provides phase balance under weld-cooling conditions and increases the transformation temperature of the α-phase to γ-phase, increasing the fraction of γ-phase as well as decreasing the precipitation of Cr2N. In the anodic polarization test, the addition of nitrogen gas in the Ar shielding gas improved values of the electrochemical parameters, compared to the Pure Ar. Also, in the erosion-corrosion test, the HDSS welded with shielding gas containing N 2 decreased the weight loss, compared to HDSS welded with the Ar pure gas. This result showed the resistance of erosion-corrosion was increased due to increasing the fraction of γ-phase and the stability of passive film according to the addition N 2 gas to the Ar shielding gas. As a result, the addition of nitrogen gas to the shielding gas improved the resistance of erosion-corrosion

  6. Concrete Cracking Prediction Including the Filling Proportion of Strand Corrosion Products

    Science.gov (United States)

    Wang, Lei; Dai, Lizhao; Zhang, Xuhui; Zhang, Jianren

    2016-01-01

    The filling of strand corrosion products during concrete crack propagation is investigated experimentally in the present paper. The effects of stirrups on the filling of corrosion products and concrete cracking are clarified. A prediction model of crack width is developed incorporating the filling proportion of corrosion products and the twisting shape of the strand. Experimental data on cracking angle, crack width, and corrosion loss obtained from accelerated corrosion tests of concrete beams are presented. The proposed model is verified by experimental data. Results show that the filling extent of corrosion products varies with crack propagation. The rust filling extent increases with the propagating crack until a critical width. Beyond the critical width, the rust-filling extent remains stable. Using stirrups can decrease the critical crack width. Stirrups can restrict crack propagation and reduce the rust filling. The tangent of the cracking angle increases with increasing corrosion loss. The prediction of corrosion-induced crack is sensitive to the rust-filling extent. PMID:28772367

  7. Evaluation of the Synergistic Effect of Erosion-Corrosion on AISI 4330 Steel in Saline-Sand Multiphase Flow by Electrochemical and Gravimetric Techniques

    Directory of Open Access Journals (Sweden)

    Dario Yesid Peña Ballesteros

    2016-01-01

    Full Text Available The synergistic effects of fluid flow, sand particles, and solution pH on erosion-corrosion of AISI 4330 steel alloy in saline-sand medium were studied through a rotating cylinder electrode (RCE system by weight-loss and electrochemical measurements. The worn surface was analyzed by X-ray diffraction (XRD and scanning electron microscopy (SEM. Results show that, under all the test conditions assessed, the passivity of the steel alloy could not be maintained; as a result, an activation mechanism dominates the corrosion process of steel alloy. Furthermore, the potentiodynamic curves show that, with the increasing of the electrode flow rate and particle size, the anodic current density increased, which is due to deterioration of the electrode by the impacting slurry. Although the increase of particle size affects the anodic current density, the effect of particle size does not cause a significant change in the polarization behavior of the steel electrode. The electrochemical impedance and potentiodynamic curves suggest that erosion-corrosion phenomenon of the ASISI 4330 steel is under mixed control of mass transport and charge transfer. The inductive loops formed in the impedance plots are representative of an increase in roughness of the electrode caused by the particles impacting at the surface. The change in the passivity of the steel alloy as the pH is altered plays an important role in the corrosion rate.

  8. Experimental and numerical investigation on cladding of corrosion-erosion resistant materials by a high power direct diode laser

    Science.gov (United States)

    Farahmand, Parisa

    In oil and gas industry, soil particles, crude oil, natural gas, particle-laden liquids, and seawater can carry various highly aggressive elements, which accelerate the material degradation of component surfaces by combination of slurry erosion, corrosion, and wear mechanisms. This material degradation results into the loss of mechanical properties such as strength, ductility, and impact strength; leading to detachment, delamination, cracking, and ultimately premature failure of components. Since the failure of high valued equipment needs considerable cost and time to be repaired or replaced, minimizing the tribological failure of equipment under aggressive environment has been gaining increased interest. It is widely recognized that effective management of degradation mechanisms will contribute towards the optimization of maintenance, monitoring, and inspection costs. The hardfacing techniques have been widely used to enhance the resistance of surfaces against degradation mechanisms. Applying a surface coating improves wear and corrosion resistance and ensures reliability and long-term performance of coated parts. A protective layer or barrier on the components avoids the direct mechanical and chemical contacts of tool surfaces with process media and will reduce the material loss and ultimately its failure. Laser cladding as an advanced hardfacing technique has been widely used for industrial applications in order to develop a protective coating with desired material properties. During the laser cladding, coating material is fused into the base material by means of a laser beam in order to rebuild a damaged part's surface or to enhance its surface function. In the hardfacing techniques such as atmospheric plasma spraying (APS), high velocity oxygen-fuel (HVOF), and laser cladding, mixing of coating materials with underneath surface has to be minimized in order to utilize the properties of the coating material most effectively. In this regard, laser cladding offers

  9. Nature in corrosion-erosion surface for [TiN/TiAlN]n nanometric multilayers growth on AISI 1045 steel

    Energy Technology Data Exchange (ETDEWEB)

    Caicedo, J.C., E-mail: jcaicedoangulo@gmail.com [Thin Films Group Universidad del Valle, Ciudad Universitaria Melendez, A.A. 25360, Cali (Colombia); Advanced Materials for Micro and NanoTechnology Research Group Universidad Autonoma de Occidente (Colombia); Cabrera, G. [Thin Films Group Universidad del Valle, Ciudad Universitaria Melendez, A.A. 25360, Cali (Colombia); Caicedo, H.H. [Department of Bioengineering, University of Illinois at Chicago, IL 60612 (United States); Department of Anatomy and Cell Biology, University of Illinois at Chicago, IL 60612 (United States); Amaya, C. [Thin Films Group Universidad del Valle, Ciudad Universitaria Melendez, A.A. 25360, Cali (Colombia); Hard Coating Laboratory CDT-ASTIN SENA, Cali (Colombia); Aperador, W. [Ingenieria Mecatronica, Universidad Militar Nueva Granada, Bogota (Colombia)

    2012-04-30

    The aim of this work is to characterize the electrochemical behavior of [TiN/TiAlN]n multilayer coatings under corrosion-erosion condition. The multilayers with bilayer numbers (n) of 2, 6, 12, and 24 and/or bilayer period ({Lambda}) of 1500 nm, 500 nm, 250 nm, 150 nm and 125 nm were deposited by magnetron sputtering technique on Si (100) and AISI 1045 steel substrates. Both, the TiN and the TiAlN structures for multilayer coatings were evaluated via X-ray diffraction analysis. Mechanical and tribological properties were evaluated via nanoindentation measurements and scratch test respectively. Silica particles were used as abrasive material on corrosion-erosion test in 0.5 M of H{sub 2}SO{sub 4} solution at impact angles of 30 Degree-Sign and 90 Degree-Sign over surface. The electrochemical characterization was carried out using polarization resistance technique (Tafel), in order to observe changes in corrosion rate as a function of the bilayer number (n) or the bilayer period ({Lambda}) and the impact angle. Corrosion rate values of 9115 {mu}m y for uncoated steel substrate and 2615 {mu}m y for substrate coated with n = 24 ({Lambda} = 125 nm) under an impact angle of 30 Degree-Sign were found. On the other hand, for an impact angle of 90 Degree-Sign the corrosion rate exhibited 16401 {mu}m y for uncoated steel substrate and 5331 {mu}m y for substrate coated with n = 24 ({Lambda} = 125 nm). This behavior was correlated with the curves of mass loss for both coated samples and the surface damage was analyzed via scanning electron microscopy images for the two different impact angles. These results indicate that TiN/TiAlN multilayer coatings deposited on AISI 1045 steel represent a practical solution for applications in corrosive-erosive environments. - Highlights: Black-Right-Pointing-Pointer Determination of superficial phenomenon that occurs in surface of multilayer films. Black-Right-Pointing-Pointer Innovative multilayer system [TiN/TiAlN]n electrochemical

  10. Coastal erosion's influencing factors include development, dams, wells, and climate change

    International Nuclear Information System (INIS)

    Aubrey, D.G.

    1993-01-01

    The demographic flight to the coast, begun in early civilization, continues unabated worldwide according to latest studies. The percentage of population living on the coast is expected to remain relatively constant over the next few decades, but the total numbers will increase as the population increases. Recent coastal battering by hurricanes and extratropical storms poses questions about coastal habitability and the real economics of coastal development. Repair costs are borne by private individuals as well as the public in various direct and indirect ways. As these costs escalate, it is fitting to ask what the future portends for storm and coastal-flood damage. It is known that development pressures will continue to increase along the coast, but what will happen concurrently to natural-hazard threats to this infrastructure? Though much emphasis has been placed on sea-level rise, the broader issue is climate change in general. Here, the author considers climate change in both its natural and anthropogenic perspectives. Without becoming mired in the debate about the greenhouse effect and human influence on climatic shifts, some of the broad classes of natural hazards that might accompany climate change are examined. There are several categories of possible global-change effects on coastal erosion. In the early 1980's, an Environmental Protection Agency (EPA) report postulated increases in global sea level up to 4 meters during the next 100 years. Though balanced somewhat by other, lower estimates of sea-level rise, this higher extreme grabbed public attention. During the next decade, scientists attempted to concur on a more reasonable estimate of global sea-level rise due to climate change. Recent credible estimates suggest that approximately 10 to 20 percent of EPA's earlier maximum estimate is most reasonable

  11. A study on the behaviour of corrosion-erosion at the Bearing metals by cavitation(1) (for the influence of pH)

    International Nuclear Information System (INIS)

    Lim, Uh Hoh; Lee, Jin Yeol

    1991-01-01

    Recently, due to increased occurrence of cavitation-erosion at slide bearing metals with the tendency of high speed and large output at internal combustion engine, there is a need to study the role of corrosive environments on cavitation-erosion. Therefore, this paper were investigate on the behaviour of cavitation-erosion under the change of pH environments at slide bearing metals with using piezoelectric vibratory apparatus. The main results obtained were as follows: 1. The weight loss and its rate showed to be increased according to the order of pH 2 > pH 12 > pH 7 > pH 4 environments, and also retarded extremely at pH 4 environment 2. The resistance of material on cavitation-erosion was excellent at pH 4 environment, and also was improved considerably its resistance with increasing of the space between specimen and horn tip. 3. It was showed that the incubation periods shortened with the tendency of pH 2 > pH 12 > pH 4 > pH 7 environment, and enlarged greatly at pH 7 environment. 4. The pitted holes of damaged surface under pH 4 environment showed dense aspects by comparison with pH 7 environment

  12. Corrosion/95 conference papers

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    The papers in this conference represent the latest technological advances in corrosion control and prevention. The following subject areas are covered: cathodic protection in natural waters; materials for fossil fuel combustion and conversion systems; modern problems in atmospheric corrosion; innovative ideas for controlling the decaying infrastructure; deposits and their effects on corrosion in industry; volatile high temperature and non aqueous corrosion inhibitors; corrosion of light-weight and precoated metals for automotive application; refining industry corrosion; corrosion in pulp and paper industry; arctic/cold weather corrosion; materials selection for waste incinerators and associated equipment; corrosion measurement technology; environmental cracking of materials; advancing technology in the coating industry; corrosion in gas treating; green inhibition; recent advances in corrosion control of rail equipment; velocity effects and erosion corrosion in oil and gas production; marine corrosion; corrosion of materials in nuclear systems; underground corrosion control; corrosion in potable and industrial water systems in buildings and its impact on environmental compliance; deposit related boiler tube failures; boiler systems monitoring and control; recent developments and experiences in reactive metals; microbiologically influenced corrosion; corrosion and corrosion control for steel reinforced concrete; international symposium on the use of 12 and 13 Cr stainless steels in oil and gas production environments; subsea corrosion /erosion monitoring in production facilities; fiberglass reinforced pipe and tubulars in oilfield service; corrosion control technology in power transmission and distribution; mechanisms and methods of scale and deposit control; closing the loop -- results oriented cooling system monitoring and control; and minimization of aqueous discharge

  13. METC ceramic corrosion/erosion studies: turbine-material screening tests in high-temperature, low-Btu, coal-derived-gas combustion products

    Energy Technology Data Exchange (ETDEWEB)

    Nakaishi, C.V.; Waltermire, D.M.; Hawkins, L.W.; Jarrett, T.L.

    1982-05-01

    The Morgantown Energy Technology Center, through its Ceramics Corrosion/Erosion Studies, has participated in the United States Department of Energy's High-Temperature Turbine Technology Program, Ceramic Technology Readiness. The program's overall objective is to advance the turbine firing temperature to a range of 2600/sup 0/ to 3000/sup 0/F (1700 to 1922K) with a reasonable service life using coal or coal-derived fuel. The Ceramics Corrosion/Erosion Studies' major objective was to conduct a screening test for several ceramic materials to assess their probability of survival in turbine applications. The materials were exposed to combustion products from low heating value coal-derived gas and air at several high temperatures and velocities. The combustion product composition and temperatures simulated actual environment that may be found in stationary power generating gas turbines except for the pressure levels. The results of approximately 1000 hours of accumulative exposure time of material at the specific test conditions are presented in this report.

  14. Corrosion cracking

    International Nuclear Information System (INIS)

    Goel, V.S.

    1985-01-01

    This book presents the papers given at a conference on alloy corrosion cracking. Topics considered at the conference included the effect of niobium addition on intergranular stress corrosion cracking, corrosion-fatigue cracking in fossil-fueled-boilers, fracture toughness, fracture modes, hydrogen-induced thresholds, electrochemical and hydrogen permeation studies, the effect of seawater on fatigue crack propagation of wells for offshore structures, the corrosion fatigue of carbon steels in seawater, and stress corrosion cracking and the mechanical strength of alloy 600

  15. Investigation and evaluation of erosion-corrosion status of the secondary side steam-water system at Paks Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Schunk, J.; Patek, G.; Pinter, T.; Baracska Varju, I.; Doma, A.; Kovacs, A.; Nemeth, P.; Tilky, P. [Paks Nuclear Power Plant Ltd (Hungary); Osz, J. [Budapest Univ. of Science and Economy (Hungary)

    2009-07-01

    There were four identical VVER-440 type units installed at Paks Nuclear Power Plant with 440 MW electrical capacity of each, between 1982 and 1987. Based on inherent reserve capacity of these units, the operational and maintenance experiences and examples of power upgrading abroad it was decided to increase the power of our units in a stepwise way. Presently, this upgrading project is close to finalization resulting in 500 MW electrical capacity of each unit. To realize the planned electrical power increase it was necessary to increase the primary and secondary heat power, which requested the increase of mass flow, temperature and pressure of secondary coolant flowing through the steam generators. According to the preliminary expert evaluations these increased parameters would not cause such an increase in humidity of steam leaving the turbine houses that could adversely impair our long term power upgrading plans. The steam humidity was determined on our units and the values did not even exceed the original design values. In spite of these preliminary investigations, significant accumulation of erosion-corrosion products at different places of secondary circuit was found and erosion damages of some secondary side equipment were discovered as a probable consequence of power upgrading. An extensive evaluation programme has been started involving experts and institutes of material testing, chemistry and hydrodynamics. Results and details of that work are given in our presentation. (authors)

  16. Feasibility Study of Low Force Robotic Friction Stir Process and its Effect On Cavitation Erosion and Electrochemical Corrosion for Ni Al Bronze Alloys

    Science.gov (United States)

    Ahmad, Azman; Li, Huijun; Pan, Zengxi; Cuiuri, Dominic; van Duin, Stephen; Larkin, Nathan; Polden, Joseph; Lane, Nathan

    2014-12-01

    Robotic friction stir processing (FSP) has not been widely researched to date. This is perhaps due to the limited force capabilities of industrial robots in comparison with dedicated commercial FSP equipment. When operating a FSP machine, the force used to plunge the tools may range from 5000 to 8000 N which is currently beyond the capability of most robots. However, the capacity of robotic manipulators is increasing, so low force friction stir processing is becoming feasible. The ability of the robot arm to apply a controlled force that is normal to a 3-dimensional surface without the need to reorient the workpiece makes it a very useful tool for FSP of complex components. In this analysis, a robot arm with a capacity of 2500 N is used to improve the surface properties of nickel aluminum bronze (NAB) using low force FSP. Multiple passes were applied to the surface of the test sample for a more consistent spread of the stir zone. The sample was then microhardness tested and demonstrated a 62 pct increase in surface hardness. Cavitation erosion testing of the original and processed surfaces was also performed as per ASTM G-32. The erosion rate of the processed NAB sample was 44 pct of the rate experienced by the original cast NAB sample. Finally, the corrosion potentials of FSP NAB were measured at 45 mV less anodic than the unprocessed material, indicating that the processed material is more noble relative to the cast NAB sample.

  17. Comportamiento de corrosión-erosión en recubrimientos de NbN depositados mediante sputtering magnetrón Erosion-corrosion behavior of magnetron sputtered NbN films

    Directory of Open Access Journals (Sweden)

    A Cáceres

    2012-08-01

    Full Text Available En la nueva generación de recubrimientos de uso industrial se incluye el nitruro de niobio (NbN debido a sus propiedades fisicoquímicas tales como: alta conductividad eléctrica, buenas propiedades mecánicas, alto punto de fusión e inercia química y además por ser un superconductor con temperatura crítica de 16 K. En este trabajo se reporta el efecto del sinergismo corrosión y erosión sobre recubrimientos de NbN depositados sobre acero inoxidable 304 y silicio usando los sistemas de sputtering con magnetrón balanceado y desbalanceado. Los experimentos de erosión-corrosión se estudiaron en un sistema que varió la velocidad y el ángulo de impacto de las partículas de erosión. Para ello se utilizó un lodo de partículas de SiO2 en una solución de 0,5M de H2SO4 + 3,5% NaCl y una concentración de 30% en peso de partículas de SiO2. La microestructura, morfología y composición química de las películas fueron analizadas con difracción de rayos X (DRX, microscopía electrónica de barrido (MEB y espectroscopia de fotoelectrones generados por rayos X (EFRX, respectivamente. Los resultados muestran que la resistencia a la erosión-corrosión de los recubiertos de NbN fue superior al sustrato y los mecanismos de desgaste sobre el recubrimiento dependen del ángulo de impacto y la velocidad de las partículas de erosión. Posibles razones de este comportamiento son discutidas en este trabajo.New generation PVD coatings for industrial applications include the niobium nitride (NbN due to its excellent properties such as high chemical inertness, excellent mechanical properties, high electrical conductivity, high melting point, and a superconducting transition temperature around 16 K. In this work we reported the results the study of corrosion and erosion effect on niobium nitride coatings deposited on AISI304 stainless steel using unbalanced and balanced magnetron sputtering and then it were compared to the uncoated tool steel substrate

  18. Underground pipeline corrosion

    CERN Document Server

    Orazem, Mark

    2014-01-01

    Underground pipelines transporting liquid petroleum products and natural gas are critical components of civil infrastructure, making corrosion prevention an essential part of asset-protection strategy. Underground Pipeline Corrosion provides a basic understanding of the problems associated with corrosion detection and mitigation, and of the state of the art in corrosion prevention. The topics covered in part one include: basic principles for corrosion in underground pipelines, AC-induced corrosion of underground pipelines, significance of corrosion in onshore oil and gas pipelines, n

  19. Slurry erosion and abrasion of metal-ceramic coatings

    International Nuclear Information System (INIS)

    Sagues, A.A.; Spencer, D.K.; Sethi, V.K.; Sargent, G.A.

    1987-01-01

    Four coatings, including tungsten carbide wear-resistant and cobalt-base corrosion-resistant materials, were tested for abrasion and erosion performance in silica sand and in Alundum slurries. A 1018 carbon steel sample was also tested for comparison. The abrasion tests were conducted with a wet sand rubber wheel device, whereas a slurry jet impingement apparatus was used in the erosion tests. The results revealed that the abrasive wear performance improves dramatically as the coating hardness increases. By contrast, the erosion performance was not clearly related to the hardness of the materials tested. The wear mechanisms and the suitability of the test methods to evaluate coatings are discussed

  20. Corrosion monitoring using FSM technology

    International Nuclear Information System (INIS)

    Strommen, R.; Horn, H.; Gartland, P.O.; Wold, K.; Haroun, M.

    1995-01-01

    FSM is a non-intrusive monitoring technique based on a patented principle, developed for the purpose of detection and monitoring of both general and localized corrosion, erosion, and cracking in steel and metal structures, piping systems, and vessels. Since 1991, FSM has been used for a wide range of applications, including for buried and open pipelines, process piping offshore, subsea pipelines and flowlines, applications in the nuclear power industry, and in materials, research in general. This paper describes typical applications of the FSM technology, and presents operational experience from some of the land-based and subsea installations. The paper also describes recent enhancements in the FSM technology and in the analysis of FSM readings, allowing for monitoring and detailed quantification of pitting and mesa corrosion, and of corrosion in welds

  1. Corrosion evaluation technology

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Uh Chul; Han, Jeong Ho; Nho, Kye Ho; Lee, Eun Hee; Kim, Hong Pyo; Hwang, Seong Sik; Lee, Deok Hyun; Hur, Do Haeng; Kim, Kyung Mo

    1997-09-01

    A multifrequency ACPD system was assembled which can measure very small crack. Stress corrosion cracking test system with SSRT operating high temperature was installed. Stress corrosion cracking test of newly developed alloy 600 and existing alloy 600 was carried out in steam atmosphere of 400 deg C. No crack was observed in both materials within a test period of 2,000 hrs. Corrosion fatigue test system operating at high temperature was installed in which fatigue crack was measured by CDPD. Lead enhanced the SCC of the Alloy 600 in high temperature water, had a tendency to modify a cracking morphology from intergranular to transgranular. Pit initiation preferentially occurred at Ti-rich carbide. Resistance to pit initiation decreased with increasing temperature up to 300 deg C. Test loop for erosion corrosion was designed and fabricated. Thin layer activation technique was very effective in measuring erosion corrosion. Erosion corrosion of a part of secondary side pipe was evaluated by the Check Family Codes of EPRI. Calculated values of pipe thickness by Check Family Codes coincided with the pipe thickness measured by UT with an error of {+-} 20%. Literature review on turbine failure showed that failure usually occurred in low pressure turbine rotor disc and causes of failure are stress corrosion cracking and corrosion fatigue. (author). 12 refs., 20 tabs., 77 figs.

  2. PITTING CORROSION IN EROSIVE CONDITION OF AGED 550°C CU10NI-3AL-1,3FE ALLOY IN 0,01 M NA2 SO4

    Directory of Open Access Journals (Sweden)

    Rodrigo Nascimento Liberto

    2012-09-01

    Full Text Available This study evaluates the effect of aging at 550°C on pitting corrosion of Cu10Ni-3Al-1.3Fe alloy, after potentiodynamic polarization test in 0.01 M Na2 SO4 in erosive condition. Cold rolled sheet specimens were solution treated at 900°C for 1 hour, and aged at 550°C until 1,032 hours. The investigation was carried out by potentiodynamic polarization in electrolyte consisted of 0.01 M Na2 SO4 with 10 wt. (% of Al2 O3 abrasive particles. After the polarization tests, specimens were analyzed by optical microscopy and scanning electron microscopy techniques to examine the morphology of the corroded regions. Result show that all samples present a passivity break potential (Eq that characterizes the initiation of pitting corrosion. However, it is not observed any significant change in the value of passivity break potential as a function of aging time. The mechanism of pitting corrosion in the studied alloys can be the passivity breakdown by the action of sulfate ion, followed by growth of pit by galvanic action or dissolution of the copper in cupric and cuprous ions and membrane formation of cuprous oxide over the pit

  3. Corrosion of metallic materials. Dry corrosion, aqueous corrosion and corrosion by liquid metal, methods of protection

    International Nuclear Information System (INIS)

    Helie, Max

    2015-01-01

    This book is based on a course on materials given in an engineering school. The author first gives an overview of metallurgy issues: metallic materials (pure metals, metallic alloys), defects of crystal lattices (point defects, linear defects or dislocations), equilibrium diagrams, steels and cast, thermal processing of steels, stainless steels, aluminium and its alloys, copper and its alloys. The second part addresses the properties and characterization of surfaces and interfaces: singularity of a metal surface, surface energy of a metal, energy of grain boundaries, adsorption at a material surface, metal-electrolyte interface, surface oxide-electrolyte interface, techniques of surface analysis. The third chapter addresses the electrochemical aspects of corrosion: description of the corrosion phenomenon, free enthalpy of a compound and free enthalpy of a reaction, case of dry corrosion (thermodynamic aspect, Ellingham diagram, oxidation mechanisms, experimental study, macroscopic modelling), case of aqueous corrosion (electrochemical thermodynamics and kinetics, experimental determination of corrosion rate). The fourth part addresses the different forms of aqueous corrosion: generalized corrosion (atmospheric corrosion, mechanisms and tests), localized corrosion (galvanic, pitting, cracking, intergranular, erosion and cavitation), particular cases of stress cracking (stress corrosion, fatigue-corrosion, embrittlement by hydrogen), and bi-corrosion (of non alloyed steels, of stainless steels, and of aluminium and copper alloys). The sixth chapter addresses the struggle and the protection against aqueous corrosion: methods of prevention, scope of use of main alloys, geometry-based protection of pieces, use of corrosion inhibitors, use of organic or metallic coatings, electrochemical protection. The last chapter proposes an overview of corrosion types in industrial practices: in the automotive industry, in the oil industry, in the aircraft industry, and in the

  4. Erosive wear of selected materials for fossil energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Adler, Thomas A.; Rawers, James C.; Tylczak, Joseph H.; Hawk, Jeffrey A.

    2001-01-01

    A number of materials have been evaluated to determine their erosion resistance for fossil energy applications. This is part of a larger program to study wear and corrosion at Albany Research Center. This paper will present the results for some of these materials, including FeAl, FeAl cermets, WC-Co cemented carbides, Si3N4-MoSi2, Si3N4, Stellite 6B, white cast irons and 440C steel. Trends in erosion rates due to material properties and erosive conditions will be presented. FeAl cermets performed well compared to the WC-Co cemented carbides. The interparticle spacing of the WC-Co cemented carbides correlated with the erosion rate. The erosion rate of the WC-Co cemented carbides decreased as the interparticle spacing decreased. It is important to realize that erosion resistance is not an intrinsic material property, but is a system response. A change in the wear environment can significantly alter the relative rankings of materials with respect to their wear rate. For example, at relatively low velocities, the carbides in the white cast irons are more erosion resistant than the matrix, while at higher velocities the matrix is more erosion resistant.

  5. Elevated temperature erosion studies on some materials for high temperature applications

    International Nuclear Information System (INIS)

    Zhou Jianren.

    1991-01-01

    The surface degradation of materials due to high temperature erosion or combined erosion corrosion is a serious problem in many industrial and aeronautical applications. As such, it has become an important design consideration in many situations. The materials investigated in the present studies are stainless steels, Ti-6Al-4V, alumina ceramics, with and without silicate glassy phase, and zirconia. These are some of the potential materials for use in the high temperature erosive-corrosive environments. The erosion or erosion-corrosion experiments were performed in a high temperature sand-blast type of test rig. The variables studied included the temperature, material composition, heat treatment condition, impingement velocity and angle, erodent concentration, etc. The morphological features of the eroded or eroded-corroded surfaces, substrate deformation, and oxide characteristics were studied by optical and scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, thermogravimetric analysis. The scratch test, single ball impact, and indentation tests were used to understand the behavior of oxide film in particle impacts. Based on these studies, the understanding of the mechanisms involved in the mechanical or combined mechanical and chemical actions in erosion was developed

  6. Corrosion/96 conference papers

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

    Topics covered by this conference include: cathodic protection in natural waters; cleaning and repassivation of building HVAC systems; worldwide opportunities in flue gas desulfurization; advancements in materials technology for use in oil and gas service; fossil fuel combustion and conversion; technology of corrosion inhibitors; computers in corrosion control--modeling and information processing; recent experiences and advances of austenitic alloys; managing corrosion with plastics; corrosion measurement technology; corrosion inhibitors for concrete; refining industry; advances in corrosion control for rail and tank trailer equipment; CO 2 corrosion--mechanisms and control; microbiologically influenced corrosion; corrosion in nuclear systems; role of corrosion in boiler failures; effects of water reuse on monitoring and control technology in cooling water applications; methods and mechanisms of scale and deposit control; corrosion detection in petroleum production lines; underground corrosion control; environmental cracking--relating laboratory results and field behavior; corrosion control in reinforced concrete structures; corrosion and its control in aerospace and military hardware; injection and process addition facilities; progress reports on the results of reinspection of deaerators inspected or repaired per RP0590 criteria; near 100% volume solids coating technology and application methods; materials performance in high temperature environments containing halides; impact of toxicity studies on use of corrosion/scale inhibitors; mineral scale deposit control in oilfield related operations; corrosion in gas treating; marine corrosion; cold climate corrosion; corrosion in the pulp and paper industry; gaseous chlorine alternatives in cooling water systems; practical applications of ozone in recirculating cooling water systems; and water reuse in industry. Over 400 papers from this conference have been processed separately for inclusion on the data base

  7. Evaluation on ultrasonic examination methods applied to Ni-base alloy weld including cracks due to stress corrosion cracking found in BWR reactor internal

    International Nuclear Information System (INIS)

    Aoki, Takayuki; Kobayashi, Hiroyuki; Higuchi, Shinichi; Shimizu, Sadato

    2005-01-01

    A Ni-base alloy weld, including cracks due to stress corrosion cracking found in the reactor internal of the oldest BWR in Japan, Tsuruga unit 1, in 1999, was examined by three (3) types of UT method. After this examination, a depth of each crack was confirmed by carrying out a little excavation with a grinder and PT examination by turns until each crack disappeared. Then, the depth measured by the former method was compared with the one measured by the latter method. In this fashion, performances of the UT methods were verified. As a result, a combination of the three types of UT method was found to meet the acceptance criteria given by ASME Sec.XI Appendix VIII, Performance Demonstration for Ultrasonic Examination Systems-Supplement 6. In this paper, the results of the UT examination described above and their evaluation are discussed. (author)

  8. A review of the erosion of thermal barrier coatings

    International Nuclear Information System (INIS)

    Wellman, R G; Nicholls, J R

    2007-01-01

    The application of thermal barrier coatings (TBCs) to components with internal cooling in the hot gas stream of gas turbine engines has facilitated a steep increase in the turbine entry temperature and the associated increase in performance and efficiency of gas turbine engines. However, TBCs are susceptible to various life limiting issues associated with their operating environment including erosion, corrosion, oxidation, sintering and foreign object damage (FOD). This is a review paper that examines various degradation and erosion mechanisms of TBCs, especially those produced by electron beam physical vapour deposition (EB-PVD). The results from a number of laboratory tests under various impact conditions are discussed before the different erosion and FOD mechanisms are reviewed. The transitions between the various erosion mechanisms are discussed in terms of the D/d ratio (contact area diameter/column diameter), a relatively new concept that relates the impact size to the erosion mechanism. The effects of ageing, dopant additions and calcium-magnesium-alumina-silicates on the life of TBCs are examined. It is shown that while ageing increases the erosion rate of EB-PVD TBCs, ageing of plasma sprayed TBCs in fact lowers the erosion rate. Finally modelling of EB-PVD TBCs is briefly introduced. (topical review)

  9. RESISTENCIA AL DESGASTE EROSIVO-CORROSIVO DE ACEROS AUSTENÍTICOS FERMANAL RESISTÊNCIA AO DESGASTE EROSIVO-CORROSIVO DE AÇOS AUSTENÍTICOS FERMANAL EROSIVE-CORROSIVE WEAR RESISTANCE OF FERMANAL AUSTENITIC STEELS

    Directory of Open Access Journals (Sweden)

    Willian Aperador

    2012-12-01

    the range (4.9~11.0 wt% Al - (17.49~34.3 wt% Mn - (0, 43~1.25 wt% C, which were melted in an induction furnace from high purity materials. The alloys were evaluated with respect to corrosion, wet erosion and corrosion-erosion at an impact angle of 90°. For the evaluation of corrosion a solution composed of 0.5 M NaCl and silica particles with size between 210 to 300 microns was used in order to analyze the effect of aluminum and manganese content in the resistance to erosion and corrosion-erosion of these alloys. To characterize the corrosion, response technique was used by potentiodynamic polarization curves and using the same technique as Tafel extrapolation, the microstructural characterization by scanning electron microscopy (SEM, and the composition of corrosion products were analyzed using diffraction of X-rays (XRD.

  10. Corrosion and corrosion control

    International Nuclear Information System (INIS)

    Khanna, A.S.; Totlani, M.K.

    1995-01-01

    Corrosion has always been associated with structures, plants, installations and equipment exposed to aggressive environments. It effects economy, safety and product reliability. Monitoring of component corrosion has thus become an essential requirement for the plant health and safety. Protection methods such as appropriate coatings, cathodic protection and use of inhibitors have become essential design parameters. High temperature corrosion, especially hot corrosion, is still a difficult concept to accommodate in corrosion allowance; there is a lack of harmonized system of performance testing of materials at high temperatures. In order to discuss and deliberate on these aspects, National Association for Corrosion Engineers International organised a National Conference on Corrosion and its Control in Bombay during November 28-30, 1995. This volume contains papers presented at the symposium. Paper relevant to INIS is indexed separately. refs., figs., tabs

  11. Corrosion in Electronics

    DEFF Research Database (Denmark)

    Ambat, Rajan; Gudla, Helene Virginie Conseil; Verdingovas, Vadimas

    2017-01-01

    and high density packing combined with the use of several materials, which can undergo electrochemical corrosion in the presence of water film formed due to humidity exposure and bias conditions on the PCBA surface. This article provides a short review of the corrosion reliability issues of electronics due...... to the use of electronics under varying humidity conditions. Important PCBA aspects, which are fundamental to the corrosion cell formation under humid conditions, are discussed. Effect of hygroscopic residues from the process and service and their role in assisting water film build up and corrosion...... is presented. Various failure modes resulting from the corrosion and influence factors are discussed including humid and gaseous conditions....

  12. Post-corrosive injuries of upper gastrointestinal tract.

    Science.gov (United States)

    Chibishev, A; Simonovska, N; Shikole, A

    2010-01-01

    Acute poisonings with corrosive substances may cause serious chemical injuries to upper gastrointestinal tract, the most common location being the esophagus and the stomach. If the patient survives the acute phase of the poisoning, regenerative response may result in esophageal and/or gastric stenosis and increased risk for esophageal cancer. Acute corrosive intoxications pose a major problem in clinical toxicology since the most commonly affected population are the young with psychic disorders, suicidal intent and alcohol addiction. In establishing the diagnosis of acute corrosive poisonings, the severity of the post-corrosive endoscopic changes of the esophagus, stomach and duodenum is of major importance. According to Holinder and Fridman classification, post-corrosive endoscopic changes are classified in three degrees: First degree--superficial damage associated with hyperthermia, epithelial desquamation and mucous edema. Second degree--transmucous damage affecting all of the mucosal layers, followed by exudation, erosions and ulcerations. Third degree--transmural damage associated with ulcer's penetration in the deep layers of the tissue and neighboring organs. Severity of the lesions depends on the nature, quantity and concentration of the corrosive substance, the duration of exposure and current state of the exposed organs. Most often caustic injuries occur to the esophagus and stomach since the corrosive substance remains there for a longer period of time. Treatment of the acute corrosive intoxications include: neutralization of corrosive agents, antibiotics, corticosteroids, anti-secretory therapy, nutritional support, collagen synthesis inhibitors, esophageal dilation and stent placement, and surgery. The most common complications that may appear are: perforation, gastrointestinal bleeding, sepsis, esophageal strictures and stenosis, stenosis of gastric antrum and pylorus, cancer of the esophagus and the stomach. Today, owing to the substantially enhanced

  13. Corrosion research from the practical view - 1987

    International Nuclear Information System (INIS)

    Behrens, D.; Rahmel, A.; Baselt, J.P.

    1987-09-01

    This volume contains brief descriptions of R+D projects in corrosion research, including those just terminated, those still going on, and those due to begin soon. On the whole, the brief accounts cover 133 individual projects. The topics of the nine project groups are: Hydrogen-induced material damage; stress-cracking corrosion; fatigue cracking corrosion and local corrosion; fluid-flow-induced corrosion; high-temperature corrosion; material behaviour in waters and soils; corrosion in special media; material behaviour in seawater; corrosion protection by means of coatings and coverings; testing procedures for detecting material damage due to corrosion. (orig./MM) [de

  14. Erosive gastritis

    International Nuclear Information System (INIS)

    Mohammed, S.H.; Conrad, C.; Kjoergaad, J.

    1982-01-01

    Erosive gastritis is a well-defined radiologic and endoscopic entity. It is one of the common causes of upper gastrointestinal bleeding, yet it is seldom diagnosed and often confused with a number of other diseases. This communication re-emphasizes the characteristic endoscopic and radiologic features of erosive gastritis and its differential diagnosis. Two representative cases are reported. (orig.)

  15. Corrosion behaviour of materials selected for FMIT lithium system

    Energy Technology Data Exchange (ETDEWEB)

    Bazinet, G.D.; Brehm, W.F.

    1983-09-01

    The corrosion behavior of selected materials in a liquid lithium environment was studied in support of system and component designs for the Fusion Materials Irradiation Test (FMIT) Facility. Testing conditions ranged from about 3700 to about6500 hours of exposure to flowing lithium at temperatures from 230/sup 0/ to 270/sup 0/C and static lithium at temperatures from 200/sup 0/ to 500/sup 0/C. Principal areas of investigation included lithium corrosion/erosion effects on FMIT lithium system baseline and candidate materials. Material coupons and full-size prototypic components were evaluated to determine corrosion rates, fatigue crack growth rates, structural compatibility, and component acceptability for the lithium system. Based on the results of these studies, concerns regarding system materials and component designs were satisfactorily resolved to support a 20-year design life requirement for the FMIT lithium system.

  16. Corrosion behaviour of materials selected for FMIT lithium system

    International Nuclear Information System (INIS)

    Bazinet, G.D.; Brehm, W.F.

    1983-01-01

    The corrosion behavior of selected materials in a liquid lithium environment was studied in support of system and component designs for the Fusion Materials Irradiation Test (FMIT) Facility. Testing conditions ranged from about 3700 to about6500 hours of exposure to flowing lithium at temperatures from 230 0 to 270 0 C and static lithium at temperatures from 200 0 to 500 0 C. Principal areas of investigation included lithium corrosion/erosion effects on FMIT lithium system baseline and candidate materials. Material coupons and full-size prototypic components were evaluated to determine corrosion rates, fatigue crack growth rates, structural compatibility, and component acceptability for the lithium system. Based on the results of these studies, concerns regarding system materials and component designs were satisfactorily resolved to support a 20-year design life requirement for the FMIT lithium system

  17. Corrosion Assessment of Candidate Materials for the SHINE Subcritical Assembly Vessel and Components FY14 Report

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, Steven J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-10-01

    Laboratory corrosion testing of candidate alloys—including Zr-4 and Zr-2.5Nb representing the target solution vessel, and 316L, 2304, 304L, and 17-4 PH stainless steels representing process piping and balance-of-plant components—was performed in support of the proposed SHINE process to produce 99Mo from low-enriched uranium. The test solutions used depleted uranyl sulfate in various concentrations and incorporated a range of temperatures, excess sulfuric acid concentrations, nitric acid additions (to simulate radiolysis product generation), and iodine additions. Testing involved static immersion of coupons in solution and in the vapor above the solution, and was extended to include planned-interval tests to examine details associated with stainless steel corrosion in environments containing iodine species. A large number of galvanic tests featuring couples between a stainless steel and a zirconium-based alloy were performed, and limited vibratory horn testing was incorporated to explore potential erosion/corrosion features of compatibility. In all cases, corrosion of the zirconium alloys was observed to be minimal, with corrosion rates based on weight loss calculated to be less than 0.1 mil/year with no change in surface roughness. The resulting passive film appeared to be ZrO2 with variations in thickness that influence apparent coloration (toward light brown for thicker films). Galvanic coupling with various stainless steels in selected exposures had no discernable effect on appearance, surface roughness, or corrosion rate. Erosion/corrosion behavior was the same for zirconium alloys in uranyl sulfate solutions and in sodium sulfate solutions adjusted to a similar pH, suggesting there was no negative effect of uranium resulting from fluid dynamic conditions aggressive to the passive film. Corrosion of the candidate stainless steels was similarly modest across the entire range of exposures. However, some sensitivity to corrosion of the stainless steels was

  18. The impact of ODA microadditions into secondary system on corrosion rate reduction in VVER steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Avdeev, A.A.; Kukushkin, A.N.; Repin, D.A. [All-Russia Research and Design Inst. of Nuclear Power Machine Building (VNIIAM), Moscow (Russian Federation); Omelchuk, V.V.; Barmin, L.F. [Kola Nuclear Power Plant, Polyarnye Zori, Murmansk region (Russian Federation); Yurmanov, V.A. [N.A. Dollezhal Research and Development Inst. of Power Engineering (NIKIET), Moscow (Russian Federation); Czempik, E. [RECON GmbH, Leipzig (Germany)

    2010-07-01

    Injection of film-forming corrosion inhibitors is a challenging way of suppressing erosion-corrosion and crud induced corrosion in power stations. Films of surface-active inhibitors, such as octadecylamine (ODA) provide a diffusion barrier to penetration of corrosion-aggressive ions onto the metal surface. Erosion and corrosion tests were conducted in autoclaves and on a pilot steam generator (SG) design to look into the impact of ODA. To accelerate corrosion process tests were conducted in a more aggressive environment as compared to actual operating conditions, including high chloride concentration and stress levels. It is not only important to reduce deposition growth, but also to wash out deposits previously formed on heat exchanger surfaces. This allows to reduce the risk of local corrosion and corrosion cracking development. A number of VVER plants have conducted full-scale testing that confirmed the impact of ODA microadditions on local corrosion mitigation. Some PWR plants are testing injection of surface-active dispersants to loosen SG deposits. Multiple studies proved ODA ability to remove chlorides from smooth surfaces which allowed to reduce the rate of microcrack growth. Trial testing has shown that the rate of corrosion cracking on SG tubes was reduced by 60-70% owing to ODA injections. Such effect was due to significant reduction in chlorides absorption by the metal surface during the year of ODA injection. Tests on a pilot SG design have shown that ODA could be used for partially wash out deposits from a heating surface. This also minimizes local corrosion. The tests showed that ODA microadditions remove chlorides from microcracks and crevices on SG tubing spacer grids. The ability to wash out previously formed deposits allows to reduce risk of local corrosion and cracking. The abilities of microadditions of film-forming corrosion inhibitors identified through the above mentioned testing could be used under the VVER plant life extension program. The

  19. State of the art review of degradation processes in LMFBR materials. Volume II. Corrosion behavior

    International Nuclear Information System (INIS)

    Dillon, R.D.

    1975-01-01

    Degradation of materials exposed to Na in LMFBR service is reviewed. The degradation processes are discussed in sections on corrosion and mass transfer, erosion, wear and self welding, sodium--water reactions, and external corrosion. (JRD)

  20. Corrosion-resistant metal surfaces

    Science.gov (United States)

    Sugama, Toshifumi [Wading River, NY

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  1. Aircraft Corrosion

    Science.gov (United States)

    1981-08-01

    transport anciens dont il a fallu remplacer les panneaux extrados en raison de is corrosion profonde des lisses. Ce type d’avion a etc mis en service h partir...as six years) where lavatories are placed above the lower section of the aft pressure dome bulkhead (fig.8)., corrosion Is found in the bulkhead web ...due to leakage of toilet fluids. One of the most severe corrosion ever found In this area was with the corrosion completely penetrated through the web

  2. Corrosive Poisonings in Adults

    Science.gov (United States)

    Chibishev, Andon; Pereska, Zanina; Chibisheva, Vesna; Simonovska, Natasa

    2012-01-01

    Ingestion of corrosive substances may cause severe to serious injuries of the upper gastrointestinal tract and the poisoning can even result in death. Acute corrosive intoxications pose a major problem in clinical toxicology since the most commonly affected population are the young with psychic disorders, suicidal intent and alcohol addiction. The golden standard for determination of the grade and extent of the lesion is esophagogastroduodenoscopy performed in the first 12-24 hours following corrosive ingestion. The most common late complications are esophageal stenosis, gastric stenosis of the antrum and pyloris, and rarely carcinoma of the upper gastrointestinal tract. Treatment of the acute corrosive intoxications include: neutralization of corrosive agents, antibiotics, anti-secretory therapy, nutritional support, collagen synthesis inhibitors, esophageal dilation and stent placement, and surgery. PMID:23678319

  3. Pitting corrosion

    International Nuclear Information System (INIS)

    Allgaier, W.

    1985-01-01

    Pitting corrosion is a kind of electrolytic corrosion by which the surface of a material is locally affected owing to inhomogeneities on the part of the material or medium. The paper deals briefly with questions relating to the importance, to parameters medium or materialwise, influence on production and construction, as well as the general conditions for pitting corrosion. In particular oxygen corrosion in unalloyed and low-alloy steel, and pitting corrosion in ferritic chromium-steel and austenitic chromium-nickel (molybdenum) steel is described. (DG) [de

  4. Rainfall erosivity in Europe.

    Science.gov (United States)

    Panagos, Panos; Ballabio, Cristiano; Borrelli, Pasquale; Meusburger, Katrin; Klik, Andreas; Rousseva, Svetla; Tadić, Melita Perčec; Michaelides, Silas; Hrabalíková, Michaela; Olsen, Preben; Aalto, Juha; Lakatos, Mónika; Rymszewicz, Anna; Dumitrescu, Alexandru; Beguería, Santiago; Alewell, Christine

    2015-04-01

    Rainfall is one the main drivers of soil erosion. The erosive force of rainfall is expressed as rainfall erosivity. Rainfall erosivity considers the rainfall amount and intensity, and is most commonly expressed as the R-factor in the USLE model and its revised version, RUSLE. At national and continental levels, the scarce availability of data obliges soil erosion modellers to estimate this factor based on rainfall data with only low temporal resolution (daily, monthly, annual averages). The purpose of this study is to assess rainfall erosivity in Europe in the form of the RUSLE R-factor, based on the best available datasets. Data have been collected from 1541 precipitation stations in all European Union (EU) Member States and Switzerland, with temporal resolutions of 5 to 60 min. The R-factor values calculated from precipitation data of different temporal resolutions were normalised to R-factor values with temporal resolutions of 30 min using linear regression functions. Precipitation time series ranged from a minimum of 5 years to a maximum of 40 years. The average time series per precipitation station is around 17.1 years, the most datasets including the first decade of the 21st century. Gaussian Process Regression (GPR) has been used to interpolate the R-factor station values to a European rainfall erosivity map at 1 km resolution. The covariates used for the R-factor interpolation were climatic data (total precipitation, seasonal precipitation, precipitation of driest/wettest months, average temperature), elevation and latitude/longitude. The mean R-factor for the EU plus Switzerland is 722 MJ mm ha(-1) h(-1) yr(-1), with the highest values (>1000 MJ mm ha(-1) h(-1) yr(-1)) in the Mediterranean and alpine regions and the lowest (<500 MJ mm ha(-1) h(-1) yr(-1)) in the Nordic countries. The erosivity density (erosivity normalised to annual precipitation amounts) was also the highest in Mediterranean regions which implies high risk for erosive events and floods

  5. Corrosion protection and control using nanomaterials

    CERN Document Server

    Cook, R

    2012-01-01

    This book covers the use of nanomaterials to prevent corrosion. The first section deals with the fundamentals of corrosion prevention using nanomaterials. Part two includes a series of case studies and applications of nanomaterials for corrosion control.$bCorrosion is an expensive and potentially dangerous problem in many industries. The potential application of different nanostructured materials in corrosion protection, prevention and control is a subject of increasing interest. Corrosion protection and control using nanomaterials explores the potential use of nanotechnology in corrosion control. The book is divided into two parts. Part one looks at the fundamentals of corrosion behaviour and the manufacture of nanocrystalline materials. Chapters discuss the impact of nanotechnology in reducing corrosion cost, and investigate the influence of various factors including thermodynamics, kinetics and grain size on the corrosion behaviour of nanocrystalline materials. There are also chapters on electrodeposition ...

  6. Erhversbetinget erosion?

    DEFF Research Database (Denmark)

    Dige, Irene; Gjørup, Hans; Nyvad, Bente

    2012-01-01

    Baggrund – I forbindelse med dental erosion er en grundig udredning af patienten vigtig, således at årsagen til erosionernes opståen findes, og der kan iværksættes adækvat forebyggende indsats. En sådan udredning er ikke mindst vigtig, når arbejdsmiljøet mistænkes. Patienttilfælde – En 30-årig...... arbejdsskade, men ikke anerkendt, da erosioner ikke er optaget på Arbejdsskadestyrelsens liste over erhvervssygdomme. En systematisk registrering af lignende tilfælde kunne imidlertid på sigt ændre retspraksis for fremtidige patienter med arbejdsbetinget erosion....

  7. Corrosion protection

    Science.gov (United States)

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

    There has been invented a chemically bonded phosphate corrosion protection material and process for application of the corrosion protection material for corrosion prevention. A slurry of iron oxide and phosphoric acid is used to contact a warm surface of iron, steel or other metal to be treated. In the presence of ferrous ions from the iron, steel or other metal, the slurry reacts to form iron phosphates which form grains chemically bonded onto the surface of the steel.

  8. Mobile evaporator corrosion test results

    International Nuclear Information System (INIS)

    Rozeveld, A.; Chamberlain, D.B.

    1997-05-01

    Laboratory corrosion tests were conducted on eight candidates to select a durable and cost-effective alloy for use in mobile evaporators to process radioactive waste solutions. Based on an extensive literature survey of corrosion data, three stainless steel alloys (304L, 316L, AL-6XN), four nickel-based alloys (825, 625, 690, G-30), and titanium were selected for testing. The corrosion tests included vapor phase, liquid junction (interface), liquid immersion, and crevice corrosion tests on plain and welded samples of candidate materials. Tests were conducted at 80 degrees C for 45 days in two different test solutions: a nitric acid solution. to simulate evaporator conditions during the processing of the cesium ion-exchange eluant and a highly alkaline sodium hydroxide solution to simulate the composition of Tank 241-AW-101 during evaporation. All of the alloys exhibited excellent corrosion resistance in the alkaline test solution. Corrosion rates were very low and localized corrosion was not observed. Results from the nitric acid tests showed that only 316L stainless steel did not meet our performance criteria. The 316L welded interface and crevice specimens had rates of 22.2 mpy and 21.8 mpy, respectively, which exceeds the maximum corrosion rate of 20 mpy. The other welded samples had about the same corrosion resistance as the plain samples. None of the welded samples showed preferential weld or heat-affected zone (HAZ) attack. Vapor corrosion was negligible for all alloys. All of the alloys except 316L exhibited either open-quotes satisfactoryclose quotes (2-20 mpy) or open-quotes excellentclose quotes (<2 mpy) corrosion resistance as defined by National Association of Corrosion Engineers. However, many of the alloys experienced intergranular corrosion in the nitric acid test solution, which could indicate a susceptibility to stress corrosion cracking (SCC) in this environment

  9. Corrosion Engineering.

    Science.gov (United States)

    White, Charles V.

    A description is provided for a Corrosion and Corrosion Control course offered in the Continuing Engineering Education Program at the General Motors Institute (GMI). GMI is a small cooperative engineering school of approximately 2,000 students who alternate between six-week periods of academic study and six weeks of related work experience in…

  10. Elevated temperature erosive wear of metallic materials

    International Nuclear Information System (INIS)

    Roy, Manish

    2006-01-01

    Solid particle erosion of metals and alloys at elevated temperature is governed by the nature of the interaction between erosion and oxidation, which, in turn, is determined by the thickness, pliability, morphology, adhesion characteristics and toughness of the oxide scale. The main objective of this paper is to critically review the present state of understanding of the elevated temperature erosion behaviour of metals and alloys. First of all, the erosion testing at elevated temperature is reviewed. This is followed by discussion of the essential features of elevated temperature erosion with special emphasis on microscopic observation, giving details of the erosion-oxidation (E-O) interaction mechanisms. The E-O interaction has been elaborated in the subsequent section. The E-O interaction includes E-O maps, analysis of transition criteria from one erosion mechanism to another mechanism and quantification of enhanced oxidation kinetics during erosion. Finally, the relevant areas for future studies are indicated. (topical review)

  11. Bentonite erosion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Birgersson, Martin; Boergesson, Lennart; Hedstroem, Magnus; Karnland, Ola; Nilsson, Ulf (Clay Technology AB, Lund (Sweden))

    2009-12-15

    Low saline water may reach KBS-3 repository depth, e.g. during periods of glaciation. Under such aqueous conditions, the montmorillonite part of the bentonite buffer might transform into a sol and thereby be transported away with flowing water in fractures. The primary aim with this report is to improve the understanding of the basic principles for this possible montmorillonite particle release. The report includes experimental and theoretical work performed at Clay Technology. Natural bentonite and ion-exchanged purified montmorillonite from three different geographical origins, Wyoming (U.S.), Milos (Greece) and Kutch (India) have been studied. Experimental and/or theoretical investigations have been performed with respect to: - Free swelling ability; - Rheological properties; - Rate of bentonite loss into fractures; - Filtering; - Ion exchange; - Sol formation ability; - Ion diffusion; - Mass loss due to erosion. The performed erosion experiments show that erosion does not occur in a mixed calcium/sodium montmorillonite with at least 20% calcium in exchange positions, when the external solution contains above 4 mM charge equivalents. This result is in agreement with the presented conceptual view of sol formation and measured equilibrium properties in mixed calcium/sodium montmorillonite. The findings imply that the buffer will be stable for non-glacial conditions. However, erosion due to sol formation cannot be ruled out for glacial conditions.

  12. Application of Corrosion Test for Austenitic SS 304 in PWR with Electrochemical Quartz Crystal Microbalance (EQCM)

    International Nuclear Information System (INIS)

    Park, Jeong Seok; Shin, Sang Hun; Kim, Jong Jin; Kim, Ji Hyun

    2011-01-01

    The secondary system of a pressurized water reactor (PWR) is a loop composed of: a) steam generator, b) steam transport piping, c) steam turbine and d) condenser and some optional component. The materials of these components are mainly carbon steel, different grades of stainless steel, high nickel alloys (Inconel-600 and Incoloy-800), Copper alloys. Among these materials, austenitic stainless steel 304 is widely used in tubing for large-surface condenser exposed to seawater as coolant of steam condenser. Stainless steels show much greater resistance to erosion-corrosion than copper alloys used in steam condenser tubing and are also immune to ammonia attack, ammonia induced stress corrosion cracking. Also, the chloride induced stress corrosion cracking has not been reported in stainless steel tubing in power plant condenser. Nevertheless, it is well known that stainless steels are susceptible to pitting and crevice corrosion in the seawater environment including chloride ions. Metallic materials exposed to untreated seawater suffer the well-known phenomenon of fouling consisting of the formation of an unwanted deposit that covers the surfaces in contact with the water. Five types of fouling are usually considered as biological, corrosion, particulate, chemical and precipitation fouling. Pitting corrosion is aggravated by stagnant or low flow conditions in which sludge such as corrosion of copper alloys in the secondary system can form in the tube surface. From the operational maintenance viewpoint, pitting attack has destructive effect of structural materials on operation of NPP. Countermeasures such as copper alloys replacement, water chemistry control and chemical cleaning were implemented to mitigate the pitting. Although the many studies are performed macroscopically to reduce pitting corrosion in the secondary system, little work has been done to understand mechanism of fouling formation and to confirm the quantitative analysis of the fouling between the metal

  13. Corrosion Monitors for Embedded Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Alex L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pfeifer, Kent B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Casias, Adrian L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Howell, Stephen W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorensen, Neil R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Missert, Nancy A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    We have developed and characterized novel in-situ corrosion sensors to monitor and quantify the corrosive potential and history of localized environments. Embedded corrosion sensors can provide information to aid health assessments of internal electrical components including connectors, microelectronics, wires, and other susceptible parts. When combined with other data (e.g. temperature and humidity), theory, and computational simulation, the reliability of monitored systems can be predicted with higher fidelity.

  14. New corrosion issues in gas sweetening plants

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G. (CLI International and Asperger Technologies, Houston, TX (United States))

    Gas treating plants are experiencing corrosion problems which impact on efficiency and safety. While general corrosion is not particularly hazardous in the gas processing industry, local corrosion is very dangerous since it has several different mechanisms, all of which have dangerously high rates, and it occurs at locations which are hard to find and hard to predict. A newly discovered, velocity-dependent type of corrosion is reported. It is related to yet-undefined species which cause excessively high corrosion in areas of turbulence. This accelerated corrosion is not due to erosion or cavitation, but to a diffusion-limited reaction accelerated by turbulence. A full-flow test loop was built to evaluate the corrosiveness of gas plant solutions at their normal temperature and flow rates. Test runs were conducted with Co[sub 2]-loaded amine solutions for periods of 12 days. Carbon steel specimens mounted in the test loop were examined and corrosion rates calculated. Chromium alloys were shown to be attacked by corrodents in the low-velocity part of the loop and very aggressively attacked in the high-velocity part. The tests demonstrate the need for rigorous monitoring of corrosion in areas of higher velocity such as piping elbows and other points of turbulence. 5 refs., 2 figs., 3 tabs.

  15. Corrosion of beryllium

    International Nuclear Information System (INIS)

    Mueller, J.J.; Adolphson, D.R.

    1987-01-01

    The corrosion behavior of beryllium in aqueous and elevated-temperature oxidizing environments has been extensively studied for early-intended use of beryllium in nuclear reactors and in jet and rocket propulsion systems. Since that time, beryllium has been used as a structural material in les corrosive environments. Its primary applications include gyro systems, mirror and reentry vehicle structures, and aircraft brakes. Only a small amount of information has been published that is directly related to the evaluation of beryllium for service in the less severe or normal atmospheric environments associated with these applications. Despite the lack of published data on the corrosion of beryllium in atmospheric environments, much can be deduced about its corrosion behavior from studies of aqueous corrosion and the experiences of fabricators and users in applying, handling, processing, storing, and shipping beryllium components. The methods of corrosion protection implemented to resist water and high-temperature gaseous environments provide useful information on methods that can be applied to protect beryllium for service in future long-term structural applications

  16. CORROSION ISSUES ASSOCIATED WITH AUSTENITIC STAINLESS STEEL COMPONENTS USED IN NUCLEAR MATERIALS EXTRACTION AND SEPARATION PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Louthan, M.; Sindelar, R.

    2012-12-17

    This paper illustrated the magnitude of the systems, structures and components used at the Savannah River Site for nuclear materials extraction and separation processes. Corrosion issues, including stress corrosion cracking, pitting, crevice corrosion and other corrosion induced degradation processes are discussed and corrosion mitigation strategies such as a chloride exclusion program and corrosion release testing are also discussed.

  17. Seismicity, seismology and erosion

    Science.gov (United States)

    Hovius, Niels; Meunier, Patrick; Burtin, Arnaud; Marc, Odin

    2013-04-01

    At the interface of geomorphology and seismology, patterns of erosion can be used to constrain seismic processes, and seismological instruments to determine geomorphic activity. For example, earthquakes trigger mass wasting in proportion to peak ground velocity or acceleration, modulated by local geologic and topographic conditions. This geomorphic response determines the mass balance and net topographic effect of earthquakes. It can also be used to obtain information about the distribution of seismic slip where instrumental observations are not available. Equally, seismometers can register the signals of geomorphic processes, revealing their location, type and magnitude. The high temporal resolution of such records can help determine the exact meteorological conditions that gave rise to erosion events, and the interactions between individual surface processes during such events. We will illustrate this synergy of disciplines with examples from active mountain belts around the world, including Taiwan, Japan, Papua New Guinea and the Alps.

  18. DPC materials and corrosion environments.

    Energy Technology Data Exchange (ETDEWEB)

    Ilgen, Anastasia Gennadyevna; Bryan, Charles R.; Teich-McGoldrick, Stephanie; Hardin, Ernest

    2014-10-01

    After an exposition of the materials used in DPCs and the factors controlling material corrosion in disposal environments, a survey is given of the corrosion rates, mechanisms, and products for commonly used stainless steels. Research needs are then identified for predicting stability of DPC materials in disposal environments. Stainless steel corrosion rates may be low enough to sustain DPC basket structural integrity for performance periods of as long as 10,000 years, especially in reducing conditions. Uncertainties include basket component design, disposal environment conditions, and the in-package chemical environment including any localized effects from radiolysis. Prospective disposal overpack materials exist for most disposal environments, including both corrosion allowance and corrosion resistant materials. Whereas the behavior of corrosion allowance materials is understood for a wide range of corrosion environments, demonstrating corrosion resistance could be more technically challenging and require environment-specific testing. A preliminary screening of the existing inventory of DPCs and other types of canisters is described, according to the type of closure, whether they can be readily transported, and what types of materials are used in basket construction.

  19. Copper corrosion and its relationship to solar collectors:a compendium.

    Energy Technology Data Exchange (ETDEWEB)

    Menicucci, David F.; Mahoney, Alan Roderick

    2007-07-01

    Copper has many fine qualities that make it a useful material. It is highly conductive of both heat and electricity, is ductile and workable, and reasonably resistant to corrosion. Because of these advantages, the solar water heating industry has been using it since the mid-1970s as the material of choice for collectors, the fundamental component of a solar water heating system. In most cases copper has performed flawlessly, but in some situations it has been known to fail. Pitting corrosion is the usual failure mode, but erosion can also occur. In 2000 Sandia National Laboratories and the Copper Development Association were asked to analyze the appearance of pin-hole leaks in solar collector units installed in a housing development in Arizona, and in 2002 Sandia analyzed a pitting corrosion event that destroyed a collector system at Camp Pendleton. This report includes copies of the reports and accounts of these corrosion failures, and provides a bibliography with references to many papers and articles that might be of benefit to the solar community. It consolidates in a single source information that has been accumulated at Sandia relative to copper corrosion, especially as it relates to solar water heaters.

  20. Accelerated cyclic corrosion tests

    Directory of Open Access Journals (Sweden)

    Prošek T.

    2016-06-01

    Full Text Available Accelerated corrosion testing is indispensable for material selection, quality control and both initial and residual life time prediction for bare and painted metallic, polymeric, adhesive and other materials in atmospheric exposure conditions. The best known Neutral Salt Spray (NSS test provides unrealistic conditions and poor correlation to exposures in atmosphere. Modern cyclic accelerated corrosion tests include intermittent salt spray, wet and dry phases and eventually other technical phases. They are able to predict the material performance in service more correctly as documented on several examples. The use of NSS should thus be restricted for quality control.

  1. Scientific case studies in land-use driven soil erosion in the central United States: Why soil potential and risk concepts should be included in the principles of soil health

    Directory of Open Access Journals (Sweden)

    Benjamin L. Turner

    2018-03-01

    Full Text Available Despite recent improvements in overall soil health gained through conservation agriculture, which has become a global priority in agricultural systems, soil and water-related externalities (e.g., wind and water erosion continue to persist or worsen. Using an inductive, systems approach, we tested the hypothesis that such externalities persist due to expansion of cultivation onto areas unsuitable for sustained production. To test this hypothesis, a variety of data sources and analyses were used to uncover the land and water resource dynamics underlying noteworthy cases of soil erosion (either wind or water and hydrological effects (e.g., flooding, shifting hydrographs throughout the central United States. Given the evidence, we failed to reject the hypothesis that cultivation expansion is contributing to increased soil and water externalities, since significant increases in cultivation on soils with severe erosion limitations were observed everywhere the externalities were documented. We discuss the case study results in terms of land use incentives (e.g., policy, economic, and biophysical, developing concepts of soil security, and ways to utilize case studies such as those presented to better communicate the value of soil and water resource conservation. Incorporating the tenets of soil potential and soil risk into soil health evaluations and cultivation decision-making is needed to better match the soil resource with land use and help avoid more extreme soil and water-related externalities.

  2. Soil Erosion and Agricultural Sustainability

    Science.gov (United States)

    Montgomery, D. R.

    2009-04-01

    Data drawn from a global compilation of studies support the long articulated contention that erosion rates from conventionally plowed agricultural fields greatly exceed rates of soil production, erosion under native vegetation, and long-term geological erosion. Whereas data compiled from around the world show that soil erosion under conventional agriculture exceeds both rates of soil production and geological erosion rates by up to several orders of magnitude, similar global distributions of soil production and geological erosion rates suggest an approximate balance. Net soil erosion rates in conventionally plowed fields on the order of 1 mm/yr can erode typical hillslope soil profiles over centuries to millennia, time-scales comparable to the longevity of major civilizations. Well-documented episodes of soil loss associated with agricultural activities date back to the introduction of erosive agricultural methods in regions around the world, and stratigraphic records of accelerated anthropogenic soil erosion have been recovered from lake, fluvial, and colluvial stratigraphy, as well as truncation of soil stratigraphy (such as truncated A horizons). A broad convergence in the results from studies based on various approaches employed to study ancient soil loss and rates of downstream sedimentation implies that widespread soil loss has accompanied human agricultural intensification in examples drawn from around the world. While a broad range of factors, including climate variability and society-specific social and economic contexts — such as wars or colonial relationships — all naturally influence the longevity of human societies, the ongoing loss of topsoil inferred from studies of soil erosion rates in conventional agricultural systems has obvious long-term implications for agricultural sustainability. Consequently, modern agriculture — and therefore global society — faces a fundamental question over the upcoming centuries. Can an agricultural system

  3. Thermomechanical Erosion Modelling of Baydaratskaya Bay, Russia with COSMOS

    NARCIS (Netherlands)

    Pearson, S.G.; Lubbad, R; Le, T.M.H.; Nairn, Rob

    2016-01-01

    Rapid coastal erosion threatens Arctic coastal infrastructure, including communities and industrial installations. Erosion of permafrost depends on numerous processes, including thermal and mechanical behaviour of frozen and unfrozen soil, nearshore hydrodynamics, atmospheric forcing, and the

  4. Reduction of surface erosion in fusion reactors

    International Nuclear Information System (INIS)

    Rossing, T.D.; Das, S.K.; Kaminsky, M.

    1976-01-01

    Some of the major processes leading to surface erosion in fusion reactors are reviewed briefly, including blistering by implanted gas, sputtering by ions, atoms, and neutrons, and vaporization by local heating. Surface erosion affects the structural integrity and limits the lifetime of reactor components exposed to plasma radiation. In addition, some of the processes leading to surface erosion also cause the release of plasma contaminants. Methods proposed to reduce surface erosion have included control of surface temperature, selection of materials with a favorable microstructure, chemical and mechanical treatment of surfaces, and employment of protective surface coatings, wall liners, and divertors. The advantages and disadvantages of some of these methods are discussed

  5. Corrosion inhibitors

    International Nuclear Information System (INIS)

    El Ashry, El Sayed H.; El Nemr, Ahmed; Esawy, Sami A.; Ragab, Safaa

    2006-01-01

    The corrosion inhibition efficiencies of some triazole, oxadiazole and thiadiazole derivatives for steel in presence of acidic medium have been studied by using AM1, PM3, MINDO/3 and MNDO semi-empirical SCF molecular orbital methods. Geometric structures, total negative charge on the molecule (TNC), highest occupied molecular energy level (E HOMO ), lowest unoccupied molecular energy level (E LUMO ), core-core repulsion (CCR), dipole moment (μ) and linear solvation energy terms, molecular volume (V i ) and dipolar-polarization (π *), were correlated to corrosion inhibition efficiency. Four equations were proposed to calculate corrosion inhibition efficiency. The agreement with the experimental data was found to be satisfactory; the standard deviations between the calculated and experimental results ranged between ±0.03 and ±4.18. The inhibition efficiency was closely related to orbital energies (E HOMO and E LUMO ) and μ. The correlation between quantum parameters and experimental inhibition efficiency has been validated by single point calculations for the semi-empirical AM1 structures using B3LYP/6-31G** as a higher level of theory. The proposed equations were applied to predict the corrosion inhibition efficiency of some related structures to select molecules of possible activity from a presumable library of compounds

  6. Corrosion of titanium: Part 1: aggressive environments and main forms of degradation.

    Science.gov (United States)

    Prando, Davide; Brenna, Andrea; Diamanti, Maria Vittoria; Beretta, Silvia; Bolzoni, Fabio; Ormellese, Marco; Pedeferri, MariaPia

    2017-11-11

    Titanium has outstanding corrosion resistance due to the external natural oxide protective layer formed when it is exposed to an aerated environment. Despite this, titanium may suffer different forms of corrosion in severe environments: uniform corrosion, pitting and crevice corrosion, hydrogen embrittlement, stress-corrosion cracking, fretting corrosion and erosion. In this first review, forms of corrosion affecting titanium are analyzed based on a wide literature review. For each form of corrosion, the mechanism and most severe environment are reported according to the current understanding.In the second part, this review will address the possible surface treatments that can increase corrosion resistance on commercially pure titanium: Electrochemical anodizing, thermal oxidation, chemical oxidation and bulk treatments such as alloying will be considered, highlighting the advantages of each technique.

  7. Corrosion of materials for heat exchangers and the countermeasures

    International Nuclear Information System (INIS)

    Kawamoto, Teruaki

    1978-01-01

    When the materials for heat exchangers are selected, the heat transfer performance, mechanical strength, workability, cost, corrosion resistance and so on are taken in consideration. Most of the failure of heat exchangers is due to corrosion, and the corrosion failure on cooling water side occurs frequently, to which attention is not paid much usually. The rate of occurrence of corrosion failure is overwhelmingly high in heating tubes, and the failure owing to cooling water exceeds that owing to process fluid. The material of heating tubes is mostly aluminum brass, and local failure such as pitting corrosion or stress corrosion cracking holds a majority. The cause of corrosion failure due to cooling water is mostly the poor water quality. The mechanism of corrosion of metals can be explained by the electrochemical reaction between the metals and solutions. As for the factors affecting corrosion, dissolved oxygen, pH, Cl - ions, temperature, flow velocity, and foreign matters are enumerated. Copper alloys are sensitive to the effect of polluted sea water. Erosion corrosion is caused by eddies and bubbles owing to high flow velocity, and impingement attack is caused by scratching foreign matters. The quality of fresh water affects corrosion more than sea water in case of copper alloys. The preliminary examination of water quality is essential. (Kako, I.)

  8. Erosion-Resistant Nanocoatings for Improved Energy Efficiency in Gas Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Alman, David; Marcio, Duffles

    2014-02-05

    The objective of this Stage Gate IV project was to test and substantiate the viability of an erosion-resistant nanocoating for application on compressor airfoils for gas turbines in both industrial power generation and commercial aviation applications. To effectively complete this project, the National Energy Technology Laboratory’s Office of Research & Development teamed with MDS Coating Technologies Inc. (MCT), Delta Air Lines - Technical Operations Division (Delta Tech Ops), and Calpine Corporation. The coating targeted for this application was MCT’s Next Generation Coating, version 4 (NGC-v4 - with the new registered trademark name of BlackGold®). The coating is an erosion and corrosion resistant composite nanostructured coating. This coating is comprised of a proprietary ceramic-metallic nano-composite construction which provides enhanced erosion resistance and also retains the aerodynamic geometry of the airfoils. The objective of the commercial aviation portion of the project was to substantiate the coating properties to allow certification from the FAA to apply an erosion-resistant coating in a commercial aviation engine. The goal of the series of tests was to demonstrate that the durability of the airfoils is not affected negatively with the application of the NGC v4 coating. Tests included erosion, corrosion, vibration and fatigue. The results of the testing demonstrated that the application of the coating did not negatively impact the properties of the blades, especially fatigue performance – which is of importance in acceptance for commercial aviation applications. The objective of the industrial gas turbine element of the project was to evaluate the coating as an enabling technology for inlet fogging during the operation of industrial gas turbines. Fluid erosion laboratory scale tests were conducted to simulate inlet fogging conditions. Results of these tests indicated that the application of the erosion resistant NGC-v4 nanocoating improved the

  9. A corrosive resistant heat exchanger

    Science.gov (United States)

    Richlen, S.L.

    1987-08-10

    A corrosive and erosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is pumped through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium. 3 figs., 3 tabs.

  10. Erosion and Errors

    NARCIS (Netherlands)

    Huisman, H.; Heeres, Glenn; Os, van Bertil; Derickx, Willem; Schoorl, J.M.

    2016-01-01

    Slope soil erosion is one of the main threats to archaeological sites. Several methods were applied to establish the erosion rates at archaeological sites. Digital elevation models (DEMs) from three different dates were used. We compared the elevations from these three models to estimate erosion. We

  11. Assessing storm erosion hazards

    NARCIS (Netherlands)

    Ranasinghe, Ranasinghe W M R J B; Callaghan, D.; Ciavola, Paolo; Coco, Giovanni

    2017-01-01

    The storm erosion hazard on coasts is usually expressed as an erosion volume and/or associated episodic coastline retreat. The accurate assessment of present-day and future storm erosion volumes is a key task for coastal zone managers, planners and engineers. There are four main approaches that can

  12. Mapping erosion from space

    NARCIS (Netherlands)

    Vrieling, A.

    2007-01-01

    Soil erosion by water is the most important land degradation problem worldwide. Spatial information on erosion is required for defining effective soil and water conservation strategies. Satellite remote sensing can provide relevant input to regional erosion assessment. This thesis comprises a review

  13. Corrosion and Wear Analysis in Marine Transport Constructions

    OpenAIRE

    Urbahs, A; Savkovs, K; Rijkuris, G; Andrejeva, D

    2018-01-01

    Corrosion is one of the most common naturally occurring processes studied by thermodynamics, which includes oxidation process, metal disruption, and its chemical and electrochemical effects under environmental influence. Corrosion of metal and equipment accounts for a considerable proportion of total corrosion losses, thus providing the impetus for further investigation and developments related to corrosion protection in order to provide transport systems and industry with corrosion preventiv...

  14. Stress corrosion crack growth rates and general corrosion rates at crack tips of steels in high temperature water

    International Nuclear Information System (INIS)

    Speidel, M.O.; Magdowski, R.

    1995-01-01

    The maximum stress corrosion crack growth rates for a number of structural materials (steels and nickel alloys) have been measured in 288 C water. Also, the general corrosion rates of these materials have been determined from weight loss experiments in simulated stress corrosion crack tip electrolytes at 288 C. It is shown that the stress corrosion crack growth rates are typically twenty times faster than the general corrosion rates. This correlation holds over five orders of magnitude. It is concluded that strategies to prevent stress corrosion cracking in high temperature aqueous environments might include alloys of higher general corrosion resistance

  15. Steam generator corrosion 2007; Dampferzeugerkorrosion 2007

    Energy Technology Data Exchange (ETDEWEB)

    Born, M. (ed.)

    2007-07-01

    Eiteneuer); (o) Thermodynamical calculations according to the optimization of spray alloys (Manfred Born, Juergen Korb, Ruediger W. Schuelen); (p) Thermal spraying between claim of erosion and claim of corrosion (Reinhard Polak, Franz Kremsner); (q) Flue gas-lateral cleaning of heating surfaces at operation and standstill of incineration boilers for waste, substitute fuels and biomass (Joerg Krueger); (r) Avoidance of superheater corrosion by external overheating (Reinhard Schu).

  16. Recent Natural Corrosion Inhibitors for Mild Steel: An Overview

    Directory of Open Access Journals (Sweden)

    Marko Chigondo

    2016-01-01

    Full Text Available Traditionally, reduction of corrosion has been managed by various methods including cathodic protection, process control, reduction of the metal impurity content, and application of surface treatment techniques, as well as incorporation of suitable alloys. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention in acidic media. These inhibitors slow down the corrosion rate and thus prevent monetary losses due to metallic corrosion on industrial vessels, equipment, or surfaces. Inorganic and organic inhibitors are toxic and costly and thus recent focus has been turned to develop environmentally benign methods for corrosion retardation. Many researchers have recently focused on corrosion prevention methods using green inhibitors for mild steel in acidic solutions to mimic industrial processes. This paper provides an overview of types of corrosion, corrosion process, and mainly recent work done on the application of natural plant extracts as corrosion inhibitors for mild steel.

  17. Surface engineering for corrosion and wear resistance

    National Research Council Canada - National Science Library

    Davis, J. R

    2001-01-01

    ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Pitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 Crevice Corrosion . . . . . . . . ....

  18. Simulations of corrosion product transfer with the OSCAR V1.2 code

    International Nuclear Information System (INIS)

    Dacquait, F.; Francescatto, J.; Broutin, F.; Genin, J.B.; Benier, G.; Girard, M.; You, D.; Ranchoux, G.; Bonnefon, J.; Bachet, M.; Riot, G.

    2012-09-01

    Activated Corrosion Products (ACPs) generate a radiation field in PWRs, which is the major contributor to the dose absorbed by nuclear power plant staff working during shutdown operations and maintenance. Therefore, a thorough understanding of the mechanisms that control the corrosion product transfer is of the highest importance. Since the 1970's, the R and D strategy in France has been based on experiments in test loops representative of PWR conditions, on in-situ gamma spectrometry measurements of the PWR primary system contamination and on simulation code development. The simulation of corrosion product transfers in PWR primary circuits is a major challenge since it involves many physical and chemical phenomena including: corrosion, dissolution, precipitation, erosion, deposition, convection, activation... In addition to the intrinsic difficulty of multi-physics modelling, the primary systems present severe operating conditions (300 deg. C, 150 bar, neutron flux, fluid velocity up to 15 m.s -1 and very low corrosion product concentrations). The purpose of the OSCAR code, developed by the CEA in cooperation with EDF and AREVA NP, is to predict the PWR primary system contamination by corrosion and fission products. The OSCAR code is considered to be not only a tool for numerical simulations and predictions (operational practices improvements and new-built PWRs design) but also one that might combine and organise all new knowledge useful to progress on contamination. The OSCAR code for Products of Corrosion, OSCAR PC, allows researchers to analyse the corrosion product behaviour and to calculate the ACP volume and surface activities of the primary and auxiliary systems. In the new version, OSCAR PC V1.2, the corrosion product transfer in the particulate form is enhanced and a new feature is the possibility to simulate cold shutdowns. In order to validate this version, the contamination transfer has been simulated in 5 French PWRs with different operating and

  19. 15 CFR 923.25 - Shoreline erosion/mitigation planning.

    Science.gov (United States)

    2010-01-01

    ... effects of, and studying and evaluating ways to control, or lessen the impact of, shoreline erosion... techniques and other techniques that will be used to manage the effects of erosion, including potential...

  20. Corrosion Testing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Corrosion Testing Facility is part of the Army Corrosion Office (ACO). It is a fully functional atmospheric exposure site, called the Corrosion Instrumented Test...

  1. Corrosion-Resistant Acrylic Coatings

    Science.gov (United States)

    1992-03-31

    ester solvents include ethylene glycol acceptable for anti-corrosive compositions. Blistering in monoethyl ether acetate, diethylene glycol monoethyl ...corrosion and 0 is i inch or more methyl isobutyl ketone. diethyl ketone, and cyclohexa- creepage from the scribe. Ratings of 3 or above are none. Glycol ...45 * coating is determined in accordance with ASTM ether acetate, etc. D714-56. This method describes blister size as numbers The coating has

  2. Corrosion monitoring during a chemical cleaning

    International Nuclear Information System (INIS)

    Delepine, J.; Feron, D.; Roy, M.

    1994-01-01

    In order to estimate the possible corrosion induced by the chemical cleaning, a corrosion monitoring has been realized during the cleaning of the secondary circuit (including the model boiler) of ORION loop. It included coupons and electrodes and has required a preliminary setting in laboratory. The electrochemical device which was used during the chemical cleaning included two reference electrodes (Ag/AgCl) and eight metallic electrodes (carbon steel, stainless steel, Alloy 600 and Alloy 690) for free corrosion potential monitoring, three other carbon steel electrodes for instantaneous corrosion rate measurements by polarization resistance and three coupling devices with different surface ratios between carbon steel and Alloy 600. The results showed a good agreement between corrosion rates measured by weight losses on coupons or by electrochemistry (polarization resistance), and an increase of the carbon steel corrosion rate when it was coupled with Alloy 600. (authors). 5 figs., 2 tabs., 3 refs

  3. Future and benefits of corrosion research

    International Nuclear Information System (INIS)

    Staehle, Roger W.

    2002-01-01

    The subject of corrosion is a design science. The subject of stress analysis is a design science as is the subject of heat transfer. When the subject of corrosion is considered in the framework design a clear framework of the priorities and objectives becomes apparent. Further, corrosion becomes a more explicit and important subject in the overall design, manufacturing, and operation phases of equipment: in this framework, the funding and support of corrosion work is necessary to the designers and users of equipment. The subject of corrosion is usually less important in the early stages of operation of equipment: in these early stages, the subjects. Corrosion becomes important to the longer term reliability and safety of equipment. Corrosion is often a principal determiner of design life. Corrosion is often more important after the manufacturing warranty is expired: therefore the subject is often more important to the user than to the manufacturer. In order that the subject of corrosion is considered and incorporated in the design as well as in user specifications, there must be a language and means of easily understood communication between the design-operation community and the corrosion community. For example, the designers do not understand the language of 'pitting potential': rather, they understand design life and permissible stress. Thus, corrosion must be put into terms that can be understood and utilized by designers and operators. Two methodologies have been developed for communicating effectively between the corrosion and the design communities: these are the 'Corrosion Based Design Approach' and the 'Location for Analysis Matrix.' These provide simple check off lists to designers for asking questions and assuring that credible answers have been obtained on issues that affect reliable and economic performance. Both of these subject are discussed in this presentation. The future of corrosion research is its effective linkage with design and operation of

  4. Corrosion-Activated Micro-Containers for Environmentally Friendly Corrosion Protective Coatings

    Science.gov (United States)

    Li, Wenyan; Buhrow, J. W.; Zhang, X.; Johnsey, M. N.; Pearman, B. P.; Jolley, S. T.; Calle, L. M.

    2016-01-01

    This work concerns the development of environmentally friendly encapsulation technology, specifically designed to incorporate corrosion indicators, inhibitors, and self-healing agents into a coating, in such a way that the delivery of the indicators and inhibitors is triggered by the corrosion process, and the delivery of self-healing agents is triggered by mechanical damage to the coating. Encapsulation of the active corrosion control ingredients allows the incorporation of desired autonomous corrosion control functions such as: early corrosion detection, hidden corrosion detection, corrosion inhibition, and self-healing of mechanical damage into a coating. The technology offers the versatility needed to include one or several corrosion control functions into the same coating.The development of the encapsulation technology has progressed from the initial proof-of-concept work, in which a corrosion indicator was encapsulated into an oil-core (hydrophobic) microcapsule and shown to be delivered autonomously, under simulated corrosion conditions, to a sophisticated portfolio of micro carriers (organic, inorganic, and hybrid) that can be used to deliver a wide range of active corrosion ingredients at a rate that can be adjusted to offer immediate as well as long-term corrosion control. The micro carriers have been incorporated into different coating formulas to test and optimize the autonomous corrosion detection, inhibition, and self-healing functions of the coatings. This paper provides an overview of progress made to date and highlights recent technical developments, such as improved corrosion detection sensitivity, inhibitor test results in various types of coatings, and highly effective self-healing coatings based on green chemistry. The NASA Kennedy Space Centers Corrosion Technology Lab at the Kennedy Space Center in Florida, U.S.A. has been developing multifunctional smart coatings based on the microencapsulation of environmentally friendly corrosion

  5. Environmentally Friendly Corrosion Preventative Compounds

    Science.gov (United States)

    Calle, Luz Marina; Montgomery, Eliza; Kolody, Mark; Curran, Jerry; Back, Teddy; Balles, Angela

    2012-01-01

    The objective of the Ground Systems Development and Operations Program Environmentally Friendly Corrosion Protective Coatings and Corrosion Preventive Compounds (CPCs) project is to identify, test, and develop qualification criteria for the use of environmentally friendly corrosion protective coatings and CPCs for flight hardware and ground support equipment. This document is the Final Report for Phase I evaluations, which included physical property, corrosion resistance, and NASA spaceport environment compatibility testing and analysis of fifteen CPC types. The CPCs consisted of ten different oily film CPCs and five different wax or grease CPC types. Physical property testing encompassed measuring various properties of the bulk CPCs, while corrosion resistance testing directly measured the ability of each CPC material to protect various metals against corrosion. The NASA spaceport environment compatibility testing included common tests required by NASA-STD-6001, "Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion". At the end of Phase I, CPC materials were down-selected for inclusion in the next test phases. This final report includes all data and analysis of results obtained by following the experimental test plan that was developed as part of the project. Highlights of the results are summarized by test criteria type.

  6. Thin layer activation: measuring wear and corrosion

    International Nuclear Information System (INIS)

    Delvigne, T.; Leyman, D.; Oxorn, K.

    1995-01-01

    The technique known as thin layer activation (TLA) is explained and assessed in this article. Widely used, in for example the automotive industry, TLA allows on-line monitoring of the loss of matter from a critical surface, by wear erosion and corrosion. The technique offers extremely high sensitivity thus leading to reduced test times. On-line wear phenomena can be assessed during operation of a mechanical process, even through thick engine walls. (UK)

  7. Penetration of corrosion products and corrosion-induced cracking in reinforced cementitious materials

    DEFF Research Database (Denmark)

    Michel, Alexander; Pease, Brad J.; Peterova, Adela

    2014-01-01

    -dependent concentrations of corrosion products averaged through the specimen thickness. Digital image correlation (DIC) was used to measure corrosion-induced deformations including deformations between steel and cementitious matrix as well as formation and propagation of corrosion-induced cracks. Based on experimental...... observations, a conceptual model was developed to describe the penetration of solid corrosion products into capillary pores of the cementitious matrix. Only capillary pores within a corrosion accommodating region (CAR), i.e. in close proximity of the steel reinforcement, were considered accessible...

  8. Catalytic interface erosion

    International Nuclear Information System (INIS)

    Meng, H.; Cohen, E.G.D.

    1995-01-01

    We study interface erosion processes: catalytic erosions. We present two cases. (1) The erosion of a completely occupied lattice by one single moving particle starting from somewhere inside the lattice, considering deterministic as well as probabilistic erosion rules. In the latter case, the eroded regions appear to have interfaces with continuously tunable fractal dimensions. (2) The kinetic roughening of an initially flat surface, where ballistic or diffusion-limited particles, which remain intact themselves, erode the surface coming from the outside, using the same erosion rules as in (1). Many features resembling realistic interfaces, for example, islands and inlets, are generated. The dependence of the surface width on the system size is due to both the erosion mechanism and the way particles move before reaching the surface

  9. Regional scaled mapping of gully erosion sensitivity in Western Kenya

    African Journals Online (AJOL)

    Administrator

    Pixels highlighted in this mapping can be considered as indicators of sediment erosion potential and runoff sensitivity of igneous rocks. The precision of the model for gully erosion sensitivity may be improved by including soil properties and topographic information. Key words: Gully erosion, East African Rift, Kavirondo Rift, ...

  10. Recognition and Analysis of Corrosion Failure Mechanisms

    OpenAIRE

    Steven Suess

    2006-01-01

    Corrosion has a vast impact on the global and domestic economy, and currently incurs losses of nearly $300 billion annually to the U.S. economy alone. Because of the huge impact of corrosion, it is imperative to have a systematic approach to recognizing and mitigating corrosion problems as soon as possible after they become apparent. A proper failure analysis includes collection of pertinent background data and service history, followed by visual inspection, photographic documentation, materi...

  11. Ferritic stainless steels: corrosion resistance + economy

    International Nuclear Information System (INIS)

    Remus, A.L.

    1976-01-01

    Ferritic stainless steels provide corrosion resistance at lower cost. They include Type 409, Type 439, 18SR, 20-Mo (1.6 Mo), 18-2 (2 Mo), 26-1S, E-Brite 26-1, 29 Cr-4 Mo, and 29 Cr-4 Mo-2 Ni. Their corrosion and mechanical properties are examined. Resistance to stress-corrosion cracking is an advantage compared to austenitic types

  12. Rainfall Erosivity in Europe

    DEFF Research Database (Denmark)

    Panagos, Panos; Ballabio, Cristiano; Borrelli, Pasquale

    2015-01-01

    on the best available datasets. Data have been collected from 1541 precipitation stations in all European Union (EU) Member States and Switzerland, with temporal resolutions of 5 to 60 min. The R-factor values calculated from precipitation data of different temporal resolutions were normalised to R......-factor values with temporal resolutions of 30 min using linear regression functions. Precipitation time series ranged from a minimum of 5 years to a maximum of 40 years. The average time series per precipitation station is around 17.1 years, the most datasets including the first decade of the 21st century....... Gaussian Process Regression (GPR) has been used to interpolate the R-factor station values to a European rainfall erosivity map at 1 km resolution. The covariates used for the R-factor interpolation were climatic data (total precipitation, seasonal precipitation, precipitation of driest/wettest months...

  13. Protection from erosion following wildfire

    Science.gov (United States)

    Peter R. Robichaud; William J. Elliot

    2006-01-01

    Erosion in the first year after a wildfire can be up to three orders of magnitude greater than the erosion from undisturbed forests. To mitigate potential postfire erosion, various erosion control treatments are applied on highly erodible areas with downstream resources in need of protection. Because postfire erosion rates generally decline by an order of magnitude for...

  14. Saliva and dental erosion

    Directory of Open Access Journals (Sweden)

    Marília Afonso Rabelo Buzalaf

    2012-10-01

    Full Text Available Dental erosion is a multifactorial condition. The consideration of chemical, biological and behavioral factors is fundamental for its prevention and therapy. Among the biological factors, saliva is one of the most important parameters in the protection against erosive wear. Objective: This review discusses the role of salivary factors on the development of dental erosion. Material and Methods: A search was undertaken on MeDLINe website for papers from 1969 to 2010. The keywords used in the research were "saliva", "acquired pellicle", "salivary flow", "salivary buffering capacity" and "dental erosion". Inclusion of studies, data extraction and quality assessment were undertaken independently and in duplicate by two members of the review team. Disagreements were solved by discussion and consensus or by a third party. Results: Several characteristics and properties of saliva play an important role in dental erosion. Salivary clearance gradually eliminates the acids through swallowing and saliva presents buffering capacity causing neutralization and buffering of dietary acids. Salivary flow allows dilution of the acids. In addition, saliva is supersaturated with respect to tooth mineral, providing calcium, phosphate and fluoride necessary for remineralization after an erosive challenge. Furthermore, many proteins present in saliva and acquired pellicle play an important role in dental erosion. Conclusions: Saliva is the most important biological factor affecting the progression of dental erosion. Knowledge of its components and properties involved in this protective role can drive the development of preventive measures targeting to enhance its known beneficial effects.

  15. Saliva and dental erosion

    Science.gov (United States)

    BUZALAF, Marília Afonso Rabelo; HANNAS, Angélicas Reis; KATO, Melissa Thiemi

    2012-01-01

    Dental erosion is a multifactorial condition. The consideration of chemical, biological and behavioral factors is fundamental for its prevention and therapy. Among the biological factors, saliva is one of the most important parameters in the protection against erosive wear. Objective This review discusses the role of salivary factors on the development of dental erosion. Material and Methods A search was undertaken on MEDLINE website for papers from 1969 to 2010. The keywords used in the research were "saliva", "acquired pellicle", "salivary flow", "salivary buffering capacity" and "dental erosion". Inclusion of studies, data extraction and quality assessment were undertaken independently and in duplicate by two members of the review team. Disagreements were solved by discussion and consensus or by a third party. Results Several characteristics and properties of saliva play an important role in dental erosion. Salivary clearance gradually eliminates the acids through swallowing and saliva presents buffering capacity causing neutralization and buffering of dietary acids. Salivary flow allows dilution of the acids. In addition, saliva is supersaturated with respect to tooth mineral, providing calcium, phosphate and fluoride necessary for remineralization after an erosive challenge. Furthermore, many proteins present in saliva and acquired pellicle play an important role in dental erosion. Conclusions Saliva is the most important biological factor affecting the progression of dental erosion. Knowledge of its components and properties involved in this protective role can drive the development of preventive measures targeting to enhance its known beneficial effects. PMID:23138733

  16. An evaluation method for corrosion fatigue life of steel structure considering mechanical factors

    OpenAIRE

    Wang, Huili; Qin, Sifeng; Jiang, Tao

    2018-01-01

    Steel structures in corrosive environment are often subjected to coupling effect and damage caused by corrosion and fatigue. This paper proposed a new assessment method to study corrosion fatigue life of steel structure, including the effect of cyclic loading and corrosion damage. Based on mechanical factors, the corrosion depth of structure under cyclic loading at different time intervals was defined by a mathematical model for corrosion damage. A finite element model was established to calc...

  17. Corrosion Fatigue in District Heating Water Tanks

    DEFF Research Database (Denmark)

    Maahn, Ernst Emanuel

    1996-01-01

    Three candidate materials for construction of buffer tanks for district heating water have been tested for corrosion fatigue properties in a district heating water environment. The investigation included Slow Strain Rate Testing of plain tensile specimens, crack initiation testing by corrosion...... fatigue of plain tensile specimens and crack growth rate determination for Compact Tensile Specimens under corrosion fatigue conditions. The three materials are equal with respect to stress corrosion sensibility and crack initiation. Crack growth rate is increased with a factor of 4-6 relative to an inert...

  18. Laser surface modification of stainless steels for cavitation erosion resistance

    Science.gov (United States)

    Kwok, Chi Tat

    1999-12-01

    Austenitic stainless steel UNS S31603 (Fe -17.6Cr -11.2Ni -2.5Mo -1.4Mn -0.4Si -0.03C) has higher pitting corrosion resistance but lower cavitation erosion resistance than that of UNS S30400. This is because of its lower tendency for strain induced martensitic transformation and higher stacking fault energy as compared with those of UNS S30400. In order to improve its cavitation erosion resistance, surface modification of S31603 was performed by laser surface melting and laser surface alloying using a 2-kW CW Nd-YAG laser and a 3-kW CW CO2 laser. For laser surface melting, austenitic stainless steel UNS S30400, super duplex stainless steel UNS S32760 and martensitic stainless steel UNS S42000 were also investigated for comparison purpose. For laser surface alloying, alloying materials including various elements (Co, Cr, Ni, Mo, Mn, Si & C), alloys (AlSiFe & NiCrSiB), ceramics (Si3N 4, SiC, Cr3C2, TiC, CrB & Cr2O 3) and alloys-ceramics (Co-WC, Ni-WC, Ni-Al2O3, Ni-Cr2C3) were used to modify the surface of S31603. The alloyed surface was achieved first by flame spraying or pre-placing of the alloy powder on the S31603 surface and then followed by laser surface remelting. The cavitation erosion characteristics of laser surface modified specimens in 3.5% NaCl solution at 23°C were studied by means of a 20-kHz ultrasonic vibrator at a peak-to-peak amplitude of 30 mum. In addition, their pitting corrosion behaviour was evaluated by electrochemical techniques. The microstructures, compositions, phase changes and damage mechanisms under cavitation erosion were investigated by optical microscopy, SEM, EDAX and X-ray diffractometry. Mechanical properties such as microhardness profile were also examined. The cavitation erosion resistance Re (reciprocal of the mean depth of penetration rate) of laser surface melted S31603 was found to be improved by 22% and was attributed to the existence of tensile residual stress. Improvement on the Re of S42000 was found to be 8.5 times

  19. Corrosion of Ceramic Materials

    Science.gov (United States)

    Opila, Elizabeth J.; Jacobson, Nathan S.

    1999-01-01

    Non-oxide ceramics are promising materials for a range of high temperature applications. Selected current and future applications are listed. In all such applications, the ceramics are exposed to high temperature gases. Therefore it is critical to understand the response of these materials to their environment. The variables to be considered here include both the type of ceramic and the environment to which it is exposed. Non-oxide ceramics include borides, nitrides, and carbides. Most high temperature corrosion environments contain oxygen and hence the emphasis of this chapter will be on oxidation processes.

  20. NOVEL CORROSION SENSOR FOR VISION 21 SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Heng Ban

    2004-12-01

    Advanced sensor technology is identified as a key component for advanced power systems for future energy plants that would have virtually no environmental impact. This project intends to develop a novel high temperature corrosion sensor and subsequent measurement system for advanced power systems. Fireside corrosion is the metal loss caused by chemical reactions on surfaces exposed to the combustion environment. Such corrosion is the leading mechanism for boiler tube failures and has emerged to be a significant concern for current and future energy plants due to the introduction of technologies targeting emissions reduction, efficiency improvement, or fuel/oxidant flexibility. Corrosion damage can lead to catastrophic equipment failure, explosions, and forced outages. Proper management of corrosion requires real-time indication of corrosion rate. However, short-term, on-line corrosion monitoring systems for fireside corrosion remain a technical challenge to date due to the extremely harsh combustion environment. The overall objective of this proposed project is to develop a technology for on-line corrosion monitoring based on a new concept. This report describes the initial results from the first-year effort of the three-year study that include laboratory development and experiment, and pilot combustor testing.

  1. Computer-Aided Corrosion Program Management

    Science.gov (United States)

    MacDowell, Louis

    2010-01-01

    This viewgraph presentation reviews Computer-Aided Corrosion Program Management at John F. Kennedy Space Center. The contents include: 1) Corrosion at the Kennedy Space Center (KSC); 2) Requirements and Objectives; 3) Program Description, Background and History; 4) Approach and Implementation; 5) Challenges; 6) Lessons Learned; 7) Successes and Benefits; and 8) Summary and Conclusions.

  2. A Course in Electrochemical and Corrosion Engineering.

    Science.gov (United States)

    Van Zee, John

    1985-01-01

    Describes a course designed to show similarities between electrochemistry and corrosion engineering and to show graduate students that electrochemical and corrosion engineering can be accomplished by extending their knowledge of chemical engineering models. Includes course outline, textbooks selected, and teaching methods used. (JN)

  3. Erosion in America

    Energy Technology Data Exchange (ETDEWEB)

    1984-03-23

    The US loses about five billion tons of soil a year from erosion, and scientists estimate that from 20 to 50% of world cropland suffers from excessive erosion. The effect of erosion is a loss in both land and water productivity. When combined with the problems of overpopulation, overgrazing, and deforestation, the environmental impacts are very serious. There are some signs that countries are beginning to adopt conservation tilling techniques, but even cooperative government programs in the US such as the 1983 Payment-in-Kind (PIK) program have had only partial success because of expanded production on marginal farmlands. 20 reference 5 figures.

  4. A Review of Field Corrosion Control and Monitoring Techniques of ...

    African Journals Online (AJOL)

    OLUWASOGO

    corrosion resistance alloy material is more effective and recommended where high rate of corrosion is predicted. (Intetech, 2010). C. Chemical Treatment. Chemicals including corrosion inhibitor, oxygen scavenger and biocide are utilized in the oil and gas industry to modify process environment in order to limit and control.

  5. A clinical index for evaluating and monitoring dental erosion

    DEFF Research Database (Denmark)

    Larsen, I B; Westergaard, J; Stoltze, K

    2000-01-01

    This study describes a new fine-scaled system for classifying initial and advanced dental erosions. The system includes the use of study casts of the teeth in an epoxy resin with an accurate surface reproduction. The severity of erosion on each tooth surface is scored according to six grades...... of severity. In addition, the presence of a Class V restoration and dental erosion on the same surface increases the erosion score, as it is assumed that the need for restorative treatment can be caused by the erosion. A high inter-examiner agreement was found when the present scoring system was used by two...

  6. General Corrosion and Localized Corrosion of the Drip Shield

    International Nuclear Information System (INIS)

    F. Hua

    2004-01-01

    The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847])

  7. General Corrosion and Localized Corrosion of the Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua

    2004-09-16

    The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847]).

  8. Measurement of erosion: Is it possible?

    NARCIS (Netherlands)

    Stroosnijder, L.

    2005-01-01

    Reasons for erosion measurements are: (1) to determine the environmental impact of erosion and conservation practices, (2) scientific erosion research; (3) development and evaluation of erosion control technology; (4) development of erosion prediction technology and (5) allocation of conservation

  9. Pitting Corrosion Topography Characteristics and Evolution Laws of LC4 Aluminum Alloy in Service Environment

    Directory of Open Access Journals (Sweden)

    LIU Zhiguo

    2017-08-01

    Full Text Available Aircraft aluminum alloy is easy to initiate pitting corrosion in the service environment, the pitting corrosion topography characteristics could directly affect the fatigue mechanical property of structure material. In order to obtain the pitting corrosion topography characteristics of LC4 aluminum alloy in the service environment, the accelerated corrosion test was carried out along the accelerated corrosion test environment spectrum which imitated the service environment spectrum, and the corrosion topography characteristic parameters of corrosion pit depth H,corrosion pit surface length L and corrosion pit surface width W were defined respectively. During the corrosion test process,the three parameters of typical corrosion pit were successively measured in different equivalent corrosion years for obtaining the corrosion pit damage size data, then the data were analysed through the statistics method and fractal theory. Further more in order to gain the pit topography characteristics in the same equivalent corrosion year and the topography evolution laws during different equivalent corrosion years were gained. The analysis results indicate that LC4 aluminum alloy corrosion pit topography characteristics in the service environment include the following:firstly, the pit topography characteristic parameters conform to the lognormal distributions in the same equivalent corrosion years; secondly,the pit topography characteristic parameters gradually reflect the fractal feature in accordance with the equivalent corrosion year increment, and the pits tend to be shallow, long and moderate wide topography character.

  10. Interrill soil erosion processes on steep slopes

    Science.gov (United States)

    Zhang, X. C. (John); Wang, Z. L.

    2017-05-01

    To date interrill erosion processes are not fully understood under different rainfall and soil conditions. The objectives are to 1) identify the interrill erosion regime and limiting process under the study condition, 2) characterize the interactive effects of rainfall intensity and flow depth on sediment transport competency and mode, and 3) develop a lumped interrill erosion model. A loess loam soil with 39% sand and 45% silt was packed to flumes and exposed to simulated rainfall. A complete factorial design with three factors was used, which included rainfall intensity (48, 62, 102, 149, and 170 mm h-1), slope gradient (17.6, 26.8, 36.4, 46.6, and 57.7%), and slope length (0.4, 0.8, 1.2, 1.6, and 2 m). Rain splash, sediment discharge in runoff, and flow velocity were measured. Results showed that rainfall intensity played a dual role not only in detaching soil materials but also in enhancing sediment transport. Sediment transport was the process limiting interrill erosion rate under the study condition. Two major sediment transport modes were identified: rainfall-driven rolling/creeping and flow-driven rolling/sliding. The relative importance of each mode was largely determined by flow depth. The competence of the flow in transporting sediment decreased downslope as flow depth increased due to increased dissipation of raindrop energy. The optimal mean flow depth for the maximal interrill erosion rates was erosion rate. The negative correlation seemed stronger for heavier rains, indicating the cushioning effects of flow depth. Lumped interrill erosion models, developed from short slopes, are likely to overestimate erosion rates. Given transport as the limiting process, the so called erodibility value, estimated with those models, is indeed sediment transportability under the study condition. The effects of slope length on interrill erosion regimes need to be studied further under a wider range of conditions.

  11. Does Canoeing Increase Streambank Erosion?

    Science.gov (United States)

    Edward A. Hansen

    1975-01-01

    Describes research on the Pine River in Michigan to determine if large increases in canoeing accelerated streambank erosion. Most erosion was natural, but people sliding and camping on streambanks created some erosion. Heavy canoe traffic was not a cause of erosion.

  12. Catastrophes caused by corrosion

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    For many years, huge attention has been paid to the problem of corrosion damage and destruction of metallic materials. Experience shows that failures due to corrosion problems are very important, and statistics at the world level shows that the damage resulting from the effects of various forms of corrosion is substantial and that, for example, in industrialized countries it reaches 4-5% of national incomes. Significant funds are determined annually for the prevention and control of corrosion...

  13. Modelling of Corrosion Cracks

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed.......Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed....

  14. Erosion of soil organic carbon: implications for carbon sequestration

    Science.gov (United States)

    Van Oost, Kristof; Van Hemelryck, Hendrik; Harden, Jennifer W.; McPherson, B.J.; Sundquist, E.T.

    2009-01-01

    Agricultural activities have substantially increased rates of soil erosion and deposition, and these processes have a significant impact on carbon (C) mineralization and burial. Here, we present a synthesis of erosion effects on carbon dynamics and discuss the implications of soil erosion for carbon sequestration strategies. We demonstrate that for a range of data-based parameters from the literature, soil erosion results in increased C storage onto land, an effect that is heterogeneous on the landscape and is variable on various timescales. We argue that the magnitude of the erosion term and soil carbon residence time, both strongly influenced by soil management, largely control the strength of the erosion-induced sink. In order to evaluate fully the effects of soil management strategies that promote carbon sequestration, a full carbon account must be made that considers the impact of erosion-enhanced disequilibrium between carbon inputs and decomposition, including effects on net primary productivity and decomposition rates.

  15. Splash erosion. A bibliometric Review

    Science.gov (United States)

    Fernández Raga, M. B.

    2012-04-01

    Ellison (1944) developed the splash board as a system for measuring splash erosion that was both cheap and reliable. Bollinne (1975), Morgan (1978, 1981). Mutchler (1967) described another different type of splash detectors according to whether they were passive or could register data. In the study mentioned above these authors included bottles, funnels, glasses, photography, markers. After that several devices has been made up like the splash sampler (Leguedois et al., 2005), soil tray (Van Dijk et al., 2002), splash funnel (Terry, 1989) and several rain cups (Fernandez-Raga et al., 2010; Molina and Llinares, 1996; Torri et al., 1987). Splash erosion research has materialized in the form of a number of papers published in international journals. The database of bibliographic references employed has been one of the most prestigious ones: theWeb of Science (ISI). The search was carried out on January 27th 2012. Among the 3x10^8 scholarly documents included in the Science Citation Index Expanded (SCI-EXPANDED) 1899 to present , the searching engine located 439 containing the word "splash erosion*", where the asterisk acts as a wildcard for any letter or group of letters. Of these, 383 were classified as articles, 87 as proceeding papers, 5 as editorial material, 2 as notes and 1 as correction. These documents have been published in 163 different journals, although four are particularly recurrent: Earth surface processes and Landforms, Catena, Soil Science Society of America Journal and Hydrological processes, with 41, 35, 35 and 26 published documents respectively. A geographic analysis of these articles has been carried out in an attempt to determine in what parts of the world research projects were making use of splash erosion. The results are that anglo-saxon countries, as USA, England and Australia dominate, particularly USA, with 130 articles. China and Japan are large communities of researches too, and some Central European countries as Belgium, France Germany

  16. Microbiological corrosion of metals

    International Nuclear Information System (INIS)

    Vladislavlev, V.V.

    1992-01-01

    Problems is considered of development of the microbiological corrosion of the NPP equipment. The main attention is paid to the selective character of microbiological corrosion in zones of welded joints of austenitic steels. It is noted that the presence of technological defects promotes growth of corrosional damages. Methods for microbiological corrosion protection are discussed

  17. Management of Reinforcement Corrosion

    DEFF Research Database (Denmark)

    Küter, André; Geiker, Mette Rica; Møller, Per

    Reinforcement corrosion is the most important cause for deterioration of reinforced concrete structures, both with regard to costs and consequences. Thermodynamically consistent descriptions of corrosion mechanisms are expected to allow the development of innovative concepts for the management...... of reinforcement corrosion....

  18. The resistance of titanium to pitting, microbially induced corrosion and corrosion in unsaturated conditions

    International Nuclear Information System (INIS)

    Shoesmith, D.W.; Ikeda, B.M.

    1997-04-01

    Titanium and its alloys (Grades-2, -12, -16) are candidate materials for Canadian nuclear waste containers on the basis of their apparent immunity to many localized corrosion processes. This simplifies markedly the effort needed to justify the use of these materials and to develop models to predict the lifetimes of containers. Here we review the pitting, microbially influenced corrosion (MIC), and corrosion under unsaturated conditions, of titanium. For all these processes, the properties of the passive oxide film are paramount in determining the metal's resistance to corrosion. A review of these oxide properties is included and the conditions to which the metal must be exposed if localized corrosion is to occur are defined. Since these conditions cannot be achieved under Canadian waste vault conditions, it can be concluded that pitting and MIC will not occur and that corrosion under unsaturated conditions is extremely unlikely. (author)

  19. Advances in Predicting Soil Erosion After Fire Using the Rangeland Hydrology and Erosion Model

    Science.gov (United States)

    Al-Hamdan, Osama Z.; Pierson, Frederick B.; Nearing, Mark A.; Williams, C. Jason; Hernandez, Mariano; Boll, Jan; Nouwakpo, Sayjro; Weltz, Mark A.; Spaeth, Kenneth E.

    2017-04-01

    The magnitude of erosion from a hillslope is governed by the availability of sediment and connectivity of overland flow and erosion processes. For undisturbed conditions, sediment is mainly detached and transported by rainsplash and sheetflow (splash-sheet) processes in bare batches, but sediment generally only travels a short distance before deposition. On recently disturbed sites (e.g., after fire), bare ground is more extensive and runoff and erosion rates are higher relative to undisturbed conditions. Increased erosion following disturbance occurs largely due to a shift from splash-sheet to concentrated-flow-dominated processes. On long-disturbed sites (e.g., after woody plant encroachment), years of soil loss can limit sediment availability and soil erosion. In contrast, recently burned landscapes typically have ample sediment available and generate high erosion rates. This presentation highlights recent advancements in hillslope erosion prediction by the Rangeland Hydrology and Erosion Model (RHEM) that accommodate recently burned conditions. The RHEM tool is a process-based model that was developed specifically for predicting hillslope runoff and erosion on rangeland ecosystems. The advancements presented here include development of empirical equations to predict erodibility parameters for conditions in which erosion by concentrated flow processes is limited (by runoff or sediment availability) and an erodibility parameter for conditions in which erosion by concentrated flow processes is the dominant erosion mechanism and sediment is amply available (burned conditions). The data used for developing and evaluating the erodibility parameter equations were obtained from rainfall simulation databases maintained by the USDA-Agricultural Research Service. The data span undisturbed, long-disturbed, and recently burned conditions. For undisturbed and long-disturbed conditions, a regression analysis was applied to derive the relationship between splash

  20. High temperature corrosion of cold worked YUS409D bellows of bellow-sealed valve in LBE

    Science.gov (United States)

    Mustari1, A. P. A.; Irwanto1, D.; Takahashi, M.

    2017-01-01

    Lead-bismuth eutectic (LBE) loop test is highly contributes to the lead-alloy-cooled fast breeder reactor (LFR) and accelerator driven system (ADS) research and development by providing comprehensive results of both corrosion and erosion phenomenon. Bellows-sealed valve is a crucial part in the LBE loop test apparatus, due to its capability of preventing corrosion on valve spring, thus improves the operation time of the system. LBE is very corrosive to stainless steel by formation of oxide layer or elemental dissolution, e.g. Ni. Thus, new type of bellows for bellows-sealed valve made of nickel free material, i.e. YUS409D, is proposed to be used in the LBE. Bellows material undergo heat treatments for mechanical improvement including cold working and annealing. The thickness reduction by the heat treatments is about 90% of initial condition. Corrosion behavior of the bellows has been studied in stagnant LBE at 500 and 600 °C for 500 hours. The oxygen concentration was controlled at about 10-7 wt%. Typical oxide layers were developed on the surface. Oxidation rate was sharply increased at 600°C.

  1. Passive Corrosion Behavior of Alloy 22

    International Nuclear Information System (INIS)

    R.B. Rebak; J.H. Payer

    2006-01-01

    Alloy 22 (NO6022) was designed to stand the most aggressive industrial applications, including both reducing and oxidizing acids. Even in the most aggressive environments, if the temperature is lower than 150 F (66 C) Alloy 22 would remain in the passive state having particularly low corrosion rates. In multi-ionic solutions that may simulate the behavior of concentrated ground water, even at near boiling temperatures, the corrosion rate of Alloy 22 is only a few nano-meters per year because the alloy is in the complete passive state. The corrosion rate of passive Alloy 22 decreases as the time increases. Immersion corrosion testing also show that the newer generation of Ni-Cr-Mo alloys may offer a better corrosion resistance than Alloy 22 only in some highly aggressive conditions such as in hot acids

  2. Investigation of erosion rates of field samples using FDOT's enhanced sediment erosion rate flume (SERF).

    Science.gov (United States)

    2013-09-01

    The first part of this project was to enhance and improve the Florida Department of Transportations : Sediment Erosion Rate Flume (SERF) device. Notable improvements include a pump repair, laser : system enhancement, installation of a digital vide...

  3. Aqueous Drainage Device Erosion: A Review of Rates, Risks, Prevention, and Repair.

    Science.gov (United States)

    Bains, Upneet; Hoguet, Ambika

    2018-01-01

    Aqueous drainage device tube erosions require prompt intervention to prevent endophthalmitis. As the use of drainage devices in glaucoma surgery continues to increase, recognizing and managing tube erosions is a pertinent issue. This review provides a comprehensive overview of tube erosions, including the rates of erosion with various types of patch grafts, the risk factors associated with erosion, and approaches to repair in order to counsel and treat our patients to prevent endophthalmitis.

  4. Dental erosion in children: a literature review.

    Science.gov (United States)

    Linnett, V; Seow, W K

    2001-01-01

    Epidemiological studies have shown that the prevalence of dental erosion in children varies widely between 2 and 57%. Changes seen in dental erosion range from removal of surface characteristics to extensive loss of tooth tissue with pulp exposure and abscess formation. Symptoms of dental erosion range from sensitivity to severe pain associated with pulp exposure. The etiology of dental erosion is dependent on the presence of extrinsic or intrinsic acid in the oral environment. Extrinsic sources of acids in children include frequent consumption of acidic foods and drinks, and acidic medications. Regurgitation of gastric contents into the mouth, as occurs in gastroesophageal reflux, is the most common source of intrinsic acid in children. A multitude of factors may modify the erosion process, such as saliva, oral hygiene practices, and presence or absence of fluoride. When dental erosion is diagnosed, it is important to investigate and identify the acid source, and to determine if the process is ongoing. The aim of treatment is to eliminate the cause of acid exposure, and to minimize the effects of acid exposure where it is not possible to remove the acid source. Restoration of the dentition involves stainless steel crowns to restore lost vertical dimension, and composite resin for esthetics.

  5. Dental erosion: causes, diagnostics and treatment.

    Directory of Open Access Journals (Sweden)

    Cecilia Sosa-Puente

    2014-12-01

    Full Text Available Despite being a commonly studied topic, it is difficult to find studies which explain the problem of dental erosion. For this article, literature was analyzed to find information on the agents which trigger dental erosion, the main diagnosis methods, the most common treatments used nowadays and the interrelationship with dental materials. The etiology of dental erosion is multifactorial, including acids, eating disorders and gastro-esophageal reflux. However, biological factors such as saliva or habits also play a part in the establishment of this condition. In order to establish a reliable diagnosis, clinical appearance becomes decisive. The Basic Index Erosive Wear Examination (BEWE, created in 2008, is an auxiliary diagnosis tool for assessing the status and progress of the erosion. Treatment should be linked to the eradication of the causative agent and it can range from simple observational monitoring of slightly affected teeth to the placement of total crowns in the most severe cases, but this will depend entirely on the extent, severity, symptoms and type of dentition. Regarding dental materials used in the treatment of eroded parts, there are glass ionomer and composite; the latter presents the greatest resistance to biodegradation when interacting with acids. Glass ionomers are the most vulnerable material while resin is seen as the most resistant. In conclusion, dental erosion has become an issue of great importance in the dental practice because of its serious impact on dental structures. Consequently, it is ranked among the most important dental disorders in the present day.

  6. Erosive Lichen Planus.

    Science.gov (United States)

    Mauskar, Melissa

    2017-09-01

    Lichen planus is an inflammatory mucocutaneous condition with a myriad of clinical manifestations. There are 3 forms of lichen planus that effect the vulva: papulosquamous, hypertrophic, and erosive. Erosive lichen planus can progress to vulvar scaring, vaginal stenosis, and squamous cell carcinoma; these long-term sequelae cause sexual distress, depression, and decreased quality of life for patients. Diagnosis is often delayed because of patient embarrassment or clinician misdiagnosis. Early recognition and treatment is essential to decreasing the morbidity of this condition. Multimodal treatment, along with a multidisciplinary approach, will improve outcomes and further clinical advances in studying this condition. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Helicobacter pylori infection, glandular atrophy and intestinal metaplasia in superficial gastritis, gastric erosion, erosive gastritis, gastric ulcer and early gastric cancer

    OpenAIRE

    Zhang, Chuan; Yamada, Nobutaka; Wu, Yun-Lin; Wen, Min; Matsuhisa, Takeshi; Matsukura, Norio

    2005-01-01

    AIM: To evaluate the histological features of gastric mucosa, including Helicobacter pylori infection in patients with early gastric cancer and endoscopically found superficial gastritis, gastric erosion, erosive gastritis, gastric ulcer.

  8. Passive, wireless corrosion sensors for transportation infrastructure.

    Science.gov (United States)

    2011-07-01

    Many industrial segments including utilities, manufacturing, government and infrastructure have an urgent need for a means to detect corrosion before significant damage occurs. Transportation infrastructure, such as bridges and roads, rely on reinfor...

  9. IN DRIFT CORROSION PRODUCTS

    Energy Technology Data Exchange (ETDEWEB)

    D.M. Jolley

    1999-12-02

    As directed by a written development plan (CRWMS M&O 1999a), a conceptual model for steel and corrosion products in the engineered barrier system (EBS) is to be developed. The purpose of this conceptual model is to assist Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift, thus allowing PAO to provide a more detailed and complete in-drift geochemical model abstraction and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near-Field Environment (NFE) Revision 2 (NRC 1999). This document provides the conceptual framework for the in-drift corrosion products sub-model to be used in subsequent PAO analyses including the EBS physical and chemical model abstraction effort. This model has been developed to serve as a basis for the in-drift geochemical analyses performed by PAO. However, the concepts discussed within this report may also apply to some near and far-field geochemical processes and may have conceptual application within the unsaturated zone (UZ) and saturated zone (SZ) transport modeling efforts.

  10. A clinical index for evaluating and monitoring dental erosion

    DEFF Research Database (Denmark)

    Larsen, I B; Westergaard, J; Stoltze, K

    2000-01-01

    This study describes a new fine-scaled system for classifying initial and advanced dental erosions. The system includes the use of study casts of the teeth in an epoxy resin with an accurate surface reproduction. The severity of erosion on each tooth surface is scored according to six grades of s...... of the oral cavity and are furthermore suitable for data analysis. The system is thereby well-suited for determining etiologic factors and monitoring the progression of erosion over time....

  11. Dune erosion above revetments

    NARCIS (Netherlands)

    Van Thiel de Vries, J.S.M.

    2012-01-01

    In a situation with a narrow dune, the dune base can be protected with a revetment to reduce dune erosion during extreme events. To quantify the effects of a revetment on storm impact, the functionality of the numerical storm impact model XBeach (Roelvink et al., 2009) is extended to account for the

  12. Corrosion of carbon steel under waste disposal conditions

    International Nuclear Information System (INIS)

    Marsh, G.

    1990-01-01

    The corrosion of carbon steel has been studied in the United Kingdom under granitic groundwater conditions, with pH between 5 and 10 and possibly substantial amounts of Cl - , SO 4 2- and HCO 3 - /CO 3 2- . Corrosion modes considered include uniform corrosion under both aerobic and anaerobic conditions; passive corrosion; localized attack in the form of pitting or crevice corrosion; and environmentally assisted cracking - hydrogen embrittlement or stress corrosion cracking. Studies of these processes are being carried out in order to predict the metal thicknesses required to give container lifetimes of 500 to 1000 years. A simple uniform corrosion model predicts a corrosion rate of around 13.4 μm/a at 20C, rising to 69 μm/a at 50C and 208 μm/a at 90C. A radiation dose of 10 5 rad/h and a G-value of 2.8 for the production of oxidizing species would account for an increase in corrosion rate of 7 μm/a. This model overestimates slightly the results actually achieved for experimental samples exposed for two years, the difference being due to a protective film formed on the samples. These corrosion rates predict that the container must be 227 mm thick to withstand uniform corrosion; however, they predict very high levels of hydrogen production. Conditions will be favourable for localized or pitting corrosion for about 125 years, leading to a maximum penetration of 160 mm. Since the exposure environment cannot be predicted precisely, one cannot state that stress corrosion cracking is impossible. Thus the container must be stress relieved. Other corrosion mechanisms such as microbial corrosion and hydrogen embrittlement are not considered significant

  13. Long Term Corrosion/Degradation Test Six Year Results

    Energy Technology Data Exchange (ETDEWEB)

    M. K. Adler Flitton; C. W. Bishop; M. E. Delwiche; T. S. Yoder

    2004-09-01

    The Subsurface Disposal Area (SDA) of the Radioactive Waste Management Complex (RWMC) located at the Idaho National Engineering and Environmental Laboratory (INEEL) contains neutron-activated metals from non-fuel, nuclear reactor core components. The Long-Term Corrosion/Degradation (LTCD) Test is designed to obtain site-specific corrosion rates to support efforts to more accurately estimate the transfer of activated elements to the environment. The test is using two proven, industry-standard methods—direct corrosion testing using metal coupons, and monitored corrosion testing using electrical/resistance probes—to determine corrosion rates for various metal alloys generally representing the metals of interest buried at the SDA, including Type 304L stainless steel, Type 316L stainless steel, Inconel 718, Beryllium S200F, Aluminum 6061, Zircaloy-4, low-carbon steel, and Ferralium 255. In the direct testing, metal coupons are retrieved for corrosion evaluation after having been buried in SDA backfill soil and exposed to natural SDA environmental conditions for times ranging from one year to as many as 32 years, depending on research needs and funding availability. In the monitored testing, electrical/resistance probes buried in SDA backfill soil will provide corrosion data for the duration of the test or until the probes fail. This report provides an update describing the current status of the test and documents results to date. Data from the one-year and three-year results are also included, for comparison and evaluation of trends. In the six-year results, most metals being tested showed extremely low measurable rates of general corrosion. For Type 304L stainless steel, Type 316L stainless steel, Inconel 718, and Ferralium 255, corrosion rates fell in the range of “no reportable” to 0.0002 mils per year (MPY). Corrosion rates for Zircaloy-4 ranged from no measurable corrosion to 0.0001 MPY. These rates are two orders of magnitude lower than those specified in

  14. Categorization of erosion control matting.

    Science.gov (United States)

    2012-05-29

    Erosion control is a critical aspect of any Georgia Department of Transportation (GDOT) : construction project, with the extreme negative impacts of high sediment loads in natural : waterways having been well documented. A variety of erosion control ...

  15. Corrosion in electronics: Overview of failures and countermeasures

    DEFF Research Database (Denmark)

    Jellesen, Morten Stendahl; Verdingovas, Vadimas; Conseil, Helene

    2014-01-01

    metals and alloys in electronic devices including aluminium, gold, copper, silver, tin, lead and their alloys. Galvanic series performed in a flux solution is presented together with examples of galvanic corrosion causing failure of electronics. Failures that find root cause in the manufacturing process......Many field failure returns of electronics are marked as “no failure found”, yet numerous of these failures are likely due to corrosion, since corrosion related failures are not easily detected during subsequent failure analysis. In some cases failures are intermittent and occur because of service...... film and potential bias of the PCBA will eventually lead to failure caused by more easy recognisable corrosion. Typical corrosion failure types seen in electronics are galvanic corrosion, electrochemical migration, and other types of bias induced corrosion. This paper describes the most commonly used...

  16. Tolerable versus actual soil erosion rates in Europe

    Science.gov (United States)

    Verheijen, F. G. A.; Jones, R. J. A.; Rickson, R. J.; Smith, C. J.

    2009-05-01

    Erosion is a major threat to soil resources in Europe, and may impair their ability to deliver a range of ecosystem goods and services. This is reflected by the European Commission's Thematic Strategy for Soil Protection, which recommends an indicator-based approach for monitoring soil erosion. Defined baseline and threshold values are essential for the evaluation of soil monitoring data. Therefore, accurate spatial data on both soil loss and soil genesis are required, especially in the light of predicted changes in climate patterns, notably frequency, seasonal distribution and intensity of precipitation. Rates of soil loss are reported that have been measured, modelled or inferred for most types of soil erosion in a variety of landscapes, by studies across the spectrum of the Earth sciences. Natural rates of soil formation can be used as a basis for setting tolerable soil erosion rates, with soil formation consisting of mineral weathering as well as dust deposition. This paper reviews the concept of tolerable soil erosion and summarises current knowledge on rates of soil formation, which are then compared to rates of soil erosion by known erosion types, for assessment of soil erosion monitoring at the European scale. A modified definition of tolerable soil erosion is proposed as 'any actual soil erosion rate at which a deterioration or loss of one or more soil functions does not occur,' actual soil erosion being 'the total amount of soil lost by all recognised erosion types.' Even when including dust deposition in soil formation rates, the upper limit of tolerable soil erosion, as equal to soil formation, is ca. 1.4 t ha - 1 yr - 1 while the lower limit is ca. 0.3 t ha - 1 yr - 1 , for conditions prevalent in Europe. Scope for spatio-temporal differentiation of tolerable soil erosion rates below this upper limit is suggested by considering (components of) relevant soil functions. Reported rates of actual soil erosion vary much more than those for soil formation

  17. Corrosion Characteristics of the SMART Materials

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Jong Hyuk; Jeong, Y. H.; Choi, B. K.; Soh, J. R.; Lee, D. J.; Choi, B. S

    2000-05-01

    This report summarized the corrosion characteristics of the candidate steam generator tubes (PT-7M, ASTM Gr.2, Inconel-600), which are considering as the core materials in SMART. Also, this evaluated the waterchemstry conditions of commercial power plant including the PWR, BWR, WWER, PHWR, RBMK plants in comparison with that of SMART. And this report described that the microstructures of as-received PT-7M, ASTM Gr.2, and Inconel-600 as the candidate materials of fuel cladding and steam generator tubes and characterized the corrosion properties of the materials, which were tested systematically in the conditions of standard, ammonia solution and ammonia nodular to evaluate the corrosion resistance.

  18. Corrosion Characteristics of the SMART Materials

    International Nuclear Information System (INIS)

    Baek, Jong Hyuk; Jeong, Y. H.; Choi, B. K.; Soh, J. R.; Lee, D. J.; Choi, B. S.

    2000-05-01

    This report summarized the corrosion characteristics of the candidate steam generator tubes (PT-7M, ASTM Gr.2, Inconel-600), which are considering as the core materials in SMART. Also, this evaluated the waterchemstry conditions of commercial power plant including the PWR, BWR, WWER, PHWR, RBMK plants in comparison with that of SMART. And this report described that the microstructures of as-received PT-7M, ASTM Gr.2, and Inconel-600 as the candidate materials of fuel cladding and steam generator tubes and characterized the corrosion properties of the materials, which were tested systematically in the conditions of standard, ammonia solution and ammonia nodular to evaluate the corrosion resistance

  19. Influence of support design on corrosion

    International Nuclear Information System (INIS)

    Krupowicz, J.J.

    1985-01-01

    The objective of the C-E/EPRI project ''Evaluation of Alternative Materials and Designs in Two Model Steam Generators,'' was to evaluate the corrosion behavior of contemporary or alternative steam generator materials under prototypic design and secondary fault water conditions. This presentation focuses on the influence of support designs on corrosion. When selecting support designs several factors must be taken into account. The alternative materials model tests were useful for comparing the corrosion resistance of materials fabricated into various support configurations including drilled support plates, broached trefoil support plates, egg crate lattice supports and Breda Termomeccanica lattice support systems

  20. Soil erosion and agricultural sustainability

    OpenAIRE

    Montgomery, David R.

    2007-01-01

    Data drawn from a global compilation of studies quantitatively confirm the long-articulated contention that erosion rates from conventionally plowed agricultural fields average 1–2 orders of magnitude greater than rates of soil production, erosion under native vegetation, and long-term geological erosion. The general equivalence of the latter indicates that, considered globally, hillslope soil production and erosion evolve to balance geologic and climate forcing, whereas conventional plow-bas...

  1. Monitoring Microbially Influenced Corrosion

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    Abstract Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria (SRB). The applicability and reliability of a number of corrosion monitoring techniques for monitoring MIC has been evaluated in experiments...... and diffusional effects and unreliable corrosion rates, when biofilm and ferrous sulphide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 by electrochemical techniques. Weight loss coupons and ER are recommended as necessary basic monitoring techniques....... EIS might be used for detection of MIC as the appearance of very large capacitances can be attributed to the combined ferrous sulphide and biofilm formation. Capacitance correlates directly with sulphide concentration in sterile sulphide media. Keywords: Corrosion monitoring, carbon steel, MIC, SRB...

  2. SRB seawater corrosion project

    Science.gov (United States)

    Bozack, M. J.

    1991-01-01

    The corrosion behavior of 2219 aluminum when exposed to seawater was characterized. Controlled corrosion experiments at three different temperatures (30, 60 and 100 C) and two different environments (seawater and 3.5 percent salt solution) were designed to elucidate the initial stages in the corrosion process. It was found that 2219 aluminum is an active catalytic surface for growth of Al2O3, NaCl, and MgO. Formation of Al2O3 is favored at lower temperatures, while MgO is favored at higher temperatures. Visible corrosion products are formed within 30 minutes after seawater exposure. Corrosion characteristics in 3.5 percent salt solution are different than corrosion in seawater. Techniques utilized were: (1) scanning electron microscopy, (2) energy dispersive x-ray spectroscopy, and (3) Auger electron spectroscopy.

  3. A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua; K. Mon; P. Pasupathi; G. Gordon

    2004-05-11

    Titanium alloy degradation modes are reviewed in relation to their performance in repository environments. General corrosion, localized corrosion, stress corrosion cracking, hydrogen induced cracking, microbially influenced corrosion, and radiation-assisted corrosion of Ti alloys are considered. With respect to the Ti Grade 7 drip shields selected for emplacement in the repository at Yucca Mountain, general corrosion, hydrogen induced cracking, and radiation-assisted corrosion will not lead to failure within the 10,000 year regulatory period; stress corrosion cracking (in the absence of disruptive events) is of no consequence to barrier performance; and localized corrosion and microbially influenced corrosion are not expected to occur. To facilitate the discussion, Ti Grades 2, 5, 7, 9, 11, 12, 16, 17, 18, and 24 are included in this review.

  4. Microbiologically Influenced Corrosion

    Science.gov (United States)

    2015-11-05

    Widdel, F. (2012) Marine sulfate-reducing bacteria cause serious corrosion of iron under electroconductive biogenic mineral crust. Envi- ronmental...inCluding oil and gas, from to 2011 [2]. Over that period of time approximately of all releases were attributed to corrosion . National ;sociati<Jn...c>fComJsicmEngineers (NACE) International [3] the cost of corrosion for onshore gas and liquid nsn1ission pipelines was $7 billion. However, there

  5. Slurry Erosion Behavior of Destabilized and Deep Cryogenically Treated Cr-Mn-Cu White Cast Irons

    Directory of Open Access Journals (Sweden)

    S. Gupta

    2016-12-01

    Full Text Available The effects of destabilization treatment and destabilization followed by cryogenic treatment have been evaluated on the microstructural evolution and sand-water slurry erosion behavior of Cr-Mn-Cu white cast irons. The phase transformations after the destabilization and cryotreatment have been characterized by bulk hardness measurement, optical and scanning electron microscopy, x-ray diffraction analysis. The static corrosion rate has been measured in tap water (with pH=7 and the erosion-corrosion behavior has been studied by slurry pot tester using sand-water slurry. The test results indicate that the cryogenic treatment has a significant effect in minimizing the as-cast retained austenite content and transforming into martensitic and bainitic matrix embedded with ultra-fine M7C3 alloy carbides. In contrast, by conventional destabilization treatment retained austenite in the matrix are not fully eliminated. The slurry erosive wear resistance has been compared with reference to destabilized and cryotreated high chromium iron samples which are commonly employed for such applications. The cryotreated Cr-Mn-Cu irons have exhibited a comparable erosive wear performance to those of high chromium irons. Higher hardness combined with improved corrosion resistance result in better slurry erosion resistance.

  6. Coatings and Corrosion Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The mission of the Coatings and Corrosion Laboratory is to develop and analyze the effectiveness of innovative coatings test procedures while evaluating the...

  7. Task E container corrosion studies: Annual report

    International Nuclear Information System (INIS)

    Bunnell, L.R.; Doremus, L.A.; Topping, J.B.; Duncan, D.R.

    1994-06-01

    The Pacific Northwest Laboratory is conducting the Solid Waste Technology Support Program (SWTSP) for Westinghouse Hanford Company (WHC). Task E is the Container Corrosion Study Portion of the SWTSP that will perform testing to provide defensible data on the corrosion of low-carbon steel, as used in drums to contain chemical and radioactive wastes at the Hanford Site. A second objective of Task E is to provide and test practical alternative materials that have higher corrosion resistance than low-carbon steel. The scope of work for fiscal year (FY) 1993 included initial testing of mild steel specimens buried in Hanford soils or exposed to atmospheric corrosion in metal storage sheds. During FY 1993, progress was made in three areas of Task E. First, exposure of test materials began at the Soil Corrosion Test Site where low-carbon steel specimens were placed in the soil in five test shafts at depths of 9 m (30 ft). Second, the corrosion measurement of low-carbon steel in the soil of two solid waste trenches continued. The total exposure time is ∼ 500 days. Third, an atmospheric corrosion test of low-carbon steel was put initiated in a metal shed (Building 2401-W) in the 200 West Area. This annual report describes the Task E efforts and provides a current status

  8. Dynamics of soil organic carbon and microbial biomass carbon in relation to water erosion and tillage erosion.

    Science.gov (United States)

    Xiaojun, Nie; Jianhui, Zhang; Zhengan, Su

    2013-01-01

    Dynamics of soil organic carbon (SOC) are associated with soil erosion, yet there is a shortage of research concerning the relationship between soil erosion, SOC, and especially microbial biomass carbon (MBC). In this paper, we selected two typical slope landscapes including gentle and steep slopes from the Sichuan Basin, China, and used the (137)Cs technique to determine the effects of water erosion and tillage erosion on the dynamics of SOC and MBC. Soil samples for the determination of (137)Cs, SOC, MBC and soil particle-size fractions were collected on two types of contrasting hillslopes. (137)Cs data revealed that soil loss occurred at upper slope positions of the two landscapes and soil accumulation at the lower slope positions. Soil erosion rates as well as distribution patterns of the erosion is the major process of soil redistribution in the gentle slope landscape, while tillage erosion acts as the dominant process of soil redistribution in the steep slope landscape. In gentle slope landscapes, both SOC and MBC contents increased downslope and these distribution patterns were closely linked to soil redistribution rates. In steep slope landscapes, only SOC contents increased downslope, dependent on soil redistribution. It is noticeable that MBC/SOC ratios were significantly lower in gentle slope landscapes than in steep slope landscapes, implying that water erosion has a negative effect on the microbial biomass compared with tillage erosion. It is suggested that MBC dynamics are closely associated with soil redistribution by water erosion but independent of that by tillage erosion, while SOC dynamics are influenced by soil redistribution by both water erosion and tillage erosion.

  9. Dynamics of Soil Organic Carbon and Microbial Biomass Carbon in Relation to Water Erosion and Tillage Erosion

    Science.gov (United States)

    Xiaojun, Nie; Jianhui, Zhang; Zhengan, Su

    2013-01-01

    Dynamics of soil organic carbon (SOC) are associated with soil erosion, yet there is a shortage of research concerning the relationship between soil erosion, SOC, and especially microbial biomass carbon (MBC). In this paper, we selected two typical slope landscapes including gentle and steep slopes from the Sichuan Basin, China, and used the 137Cs technique to determine the effects of water erosion and tillage erosion on the dynamics of SOC and MBC. Soil samples for the determination of 137Cs, SOC, MBC and soil particle-size fractions were collected on two types of contrasting hillslopes. 137Cs data revealed that soil loss occurred at upper slope positions of the two landscapes and soil accumulation at the lower slope positions. Soil erosion rates as well as distribution patterns of the erosion is the major process of soil redistribution in the gentle slope landscape, while tillage erosion acts as the dominant process of soil redistribution in the steep slope landscape. In gentle slope landscapes, both SOC and MBC contents increased downslope and these distribution patterns were closely linked to soil redistribution rates. In steep slope landscapes, only SOC contents increased downslope, dependent on soil redistribution. It is noticeable that MBC/SOC ratios were significantly lower in gentle slope landscapes than in steep slope landscapes, implying that water erosion has a negative effect on the microbial biomass compared with tillage erosion. It is suggested that MBC dynamics are closely associated with soil redistribution by water erosion but independent of that by tillage erosion, while SOC dynamics are influenced by soil redistribution by both water erosion and tillage erosion. PMID:23717530

  10. Corrosion in the oil industry

    Energy Technology Data Exchange (ETDEWEB)

    Brondel, D. (Sedco Forex, Montrouge (France)); Edwards, R. (Schlumberger Well Services, Columbus, OH (United States)); Hayman, A. (Etudes et Productions Schlumberger, Clamart (France)); Hill, D. (Schlumberger Dowell, Tulsa, OK (United States)); Mehta, S. (Schlumberger Dowell, St. Austell (United Kingdom)); Semerad, T. (Mobil Oil Indonesia, Inc., Sumatra (Indonesia))

    1994-04-01

    Corrosion costs the oil industry billions of dollars a year, a fact that makes the role of the corrosion engineer an increasingly important one. Attention is paid to how corrosion affects every aspect of exploration and production, from offshore rigs to casing. Also the role of corrosion agents such as drilling and production fluids is reviewed. Methods of control and techniques to monitor corrosion are discussed, along with an explanation of the chemical causes of corrosion. 21 figs., 32 refs.

  11. Effect of Wall Shear Stress on Corrosion Inhibitor Film Performance

    Science.gov (United States)

    Canto Maya, Christian M.

    films. Different scenarios were evaluated in this section of the work, such as the loss of corrosion inhibitor due to the formation of foam, and the effect of different substrates on the adsorption of corrosion inhibitor. Erosion/corrosion effects due to solids carried by a multiphase flow were investigated both on a small and large scale. Small scale experiments were performed in order to determine whether the corrosion inhibitor concentration was diminished because of adsorption onto the large surface area of entrained solid particles. The large scale experiments were done to evaluate the effect of mechanical erosion corrosion on inhibitor film performance, and vice versa. The analysis of the results obtained by electrochemical characterization shows that the adsorption mechanism having a corrosion inhibitor competing with water molecules for a place on the steel surface is an accurate approach to describe this phenomenon. From the experimental results obtained in the multiphase part of this research project, it can be concluded that the performance of corrosion inhibitor films is not significantly impacted by mechanical forces alone; even under the worst case scenarios tested here (standing slug and erosion/corrosion). Reduction of inhibitor performance was found to be primarily due to the loss of inhibitor due to consumption by adsorption particularly when a gas phase was present, leading to foam formation.

  12. Corrosion resistant ceramic materials

    Science.gov (United States)

    Kaun, Thomas D.

    1996-01-01

    Ceramic materials which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.

  13. Data book of anti-corrosion method

    International Nuclear Information System (INIS)

    Lee, Ui Ho

    1997-07-01

    This book deals with cases, influence, cause, standard of corrosion of steel structure, which includes bridges, steel tower, corrosion data, the ocean, ports, and RC structure for civil engineering, exterior materials of construction, building equipment pipes, processing industries such as chemical equipment, oil device, pump and coolant, environment facility like trash incinerator, and sewage process, thermal power generation and nuclear energy generation, and energy industry.

  14. Illuminating wildfire erosion and deposition patterns with repeat terrestrial lidar

    Science.gov (United States)

    Rengers, Francis K.; Tucker, G.E.; Moody, J.A.; Ebel, Brian

    2016-01-01

    Erosion following a wildfire is much greater than background erosion in forests because of wildfire-induced changes to soil erodibility and water infiltration. While many previous studies have documented post-wildfire erosion with point and small plot-scale measurements, the spatial distribution of post-fire erosion patterns at the watershed scale remains largely unexplored. In this study lidar surveys were collected periodically in a small, first-order drainage basin over a period of 2 years following a wildfire. The study site was relatively steep with slopes ranging from 17° to > 30°. During the study period, several different types of rain storms occurred on the site including low-intensity frontal storms (2.4 mm h−1) and high-intensity convective thunderstorms (79 mm h−1). These storms were the dominant drivers of erosion. Erosion resulting from dry ravel and debris flows was notably absent at the site. Successive lidar surveys were subtracted from one another to obtain digital maps of topographic change between surveys. The results show an evolution in geomorphic response, such that the erosional response after rain storms was strongly influenced by the previous erosional events and pre-fire site morphology. Hillslope and channel roughness increased over time, and the watershed armored as coarse cobbles and boulders were exposed. The erosional response was spatially nonuniform; shallow erosion from hillslopes (87% of the study area) contributed 3 times more sediment volume than erosion from convergent areas (13% of the study area). However, the total normalized erosion depth (volume/area) was highest in convergent areas. From a detailed understanding of the spatial locations of erosion, we made inferences regarding the processes driving erosion. It appears that hillslope erosion is controlled by rain splash (for detachment) and overland flow (for transport and quasi-channelized erosion), with the sites of highest erosion corresponding to locations

  15. Environmentally Friendly Coating Technology for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Johnsey, Marissa N.; Jolley, Scott T.; Pearman, Benjamin P.; Zhang, Xuejun; Fitzpatrick, Lilliana; Gillis, Mathew; Blanton, Michael; hide

    2016-01-01

    This work concerns the development of environmentally friendly encapsulation technology, specifically designed to incorporate corrosion indicators, inhibitors, and self-healing agents into a coating, in such a way that the delivery of the indicators and inhibitors is triggered by the corrosion process, and the delivery of self-healing agents is triggered by mechanical damage to the coating. Encapsulation of the active corrosion control ingredients allows the incorporation of desired autonomous corrosion control functions such as: early corrosion detection, hidden corrosion detection, corrosion inhibition, and self-healing of mechanical damage into a coating. The technology offers the versatility needed to include one or several corrosion control functions into the same coating.The development of the encapsulation technology has progressed from the initial proof-of-concept work, in which a corrosion indicator was encapsulated into an oil-core (hydrophobic) microcapsule and shown to be delivered autonomously, under simulated corrosion conditions, to a sophisticated portfolio of micro carriers (organic, inorganic, and hybrid) that can be used to deliver a wide range of active corrosion ingredients at a rate that can be adjusted to offer immediate as well as long-term corrosion control. The micro carriers have been incorporated into different coating formulas to test and optimize the autonomous corrosion detection, inhibition, and self-healing functions of the coatings. This paper provides an overview of progress made to date and highlights recent technical developments, such as improved corrosion detection sensitivity, inhibitor test results in various types of coatings, and highly effective self-healing coatings based on green chemistry.

  16. Rainfall erosivity map for Ghana

    International Nuclear Information System (INIS)

    Oduro Afriyie, K.

    1995-10-01

    Monthly rainfall data, spanning over a period of more than thirty years, were used to compute rainfall erosivity indices for various stations in Ghana, using the Fournier index, c, defined as p 2 /P, where p is the rainfall amount in the wettest month and P is the annual rainfall amount. Values of the rainfall erosivity indices ranged from 24.5 mm at Sunyani in the mid-portion of Ghana to 180.9 mm at Axim in the south western coastal portion. The indices were used to construct a rainfall erosivity map for the country. The map revealed that Ghana may be broadly divided into five major erosion risk zones. The middle sector of Ghana is generally in the low erosion risk zone; the northern sector is in the moderate to severe erosion risk zone, while the coastal sector is in the severe to extreme severe erosion risk zone. (author). 11 refs, 1 fig., 1 tab

  17. Actinides, accelerators and erosion

    Directory of Open Access Journals (Sweden)

    Fifield L.K.

    2012-10-01

    Full Text Available Fallout isotopes can be used as artificial tracers of soil erosion and sediment accumulation. The most commonly used isotope to date has been 137Cs. Concentrations of 137Cs are, however, significantly lower in the Southern Hemisphere, and furthermore have now declined to 35% of original values due to radioactive decay. As a consequence the future utility of 137Cs is limited in Australia, with many erosion applications becoming untenable within the next 20 years, and there is a need to replace it with another tracer. Plutonium could fill this role, and has the advantages that there were six times as many atoms of Pu as of 137Cs in fallout, and any loss to decay has been negligible due to the long half-lives of the plutonium isotopes. Uranium-236 is another long-lived fallout isotope with significant potential for exploitation as a tracer of soil and sediment movement. Uranium is expected to be more mobile in soils than plutonium (or caesium, and hence the 236U/Pu ratio will vary with soil depth, and so could provide an independent measure of the amount of soil loss. In this paper we discuss accelerator based ultra-sensitive measurements of plutonium and 236U isotopes and their advantages over 137Cs as tracers of soil erosion and sediment movement.

  18. Factors affecting soil erosion in Beijing mountain forestlands | Zhang ...

    African Journals Online (AJOL)

    The role of regions, vegetation types and forest stand density in controlling soil erosion were investigated in Beijing mountain forest, China. The main objective was to develop some models to estimate soil erosion under different forest conditions including regions, vegetation type, and stand density as influenced by artificial ...

  19. Archaeological analogs and corrosion

    International Nuclear Information System (INIS)

    David, D.

    2008-01-01

    In the framework of the high level and long life radioactive wastes disposal deep underground, the ANDRA built a research program on the material corrosion. In particular they aim to design containers for a very long time storage. Laboratory experiments are in progress and can be completed by the analysis of metallic archaeological objects and their corrosion after hundred years. (A.L.B.)

  20. Demystifying Controlling Copper Corrosion

    Science.gov (United States)

    The LCR systematically misses the highest health and corrosion risk sites for copper. Additionally, there are growing concerns for WWTP copper in sludges and discharge levels. There are many corrosion control differences between copper and lead. This talk explains the sometimes c...

  1. Characterization and High-Temperature Erosion Behaviour of HVOF Thermal Spray Cermet Coatings

    Science.gov (United States)

    Kumar, Pardeep; Sidhu, Buta Singh

    2016-01-01

    High-velocity oxygen fuel (HVOF) thermal spray, carbide-cermet-based coatings are usually employed in high-temperature erosive and erosive-corrosive environments. Extensive literature is available on high-temperature erosion performance of HVOF coatings under moderate to low particle flux and velocities for application in boiler tubes. This research work presents the characterization and high-temperature erosion behaviour of Cr3C2-25NiCr and WC-10Co-4Cr HVOF-sprayed coatings. Coatings were formulated on the substrate steel of type AISI 304, commonly used for the fabrication of pulverized coal burner nozzles (PCBN). Erosion testing was carried out in high-temperature air-jet erosion tester after simulating the conditions akin to that prevailing in PCBN in the boiler furnace. The coatings were tested for erosion behaviour at different angles and temperatures by freezing other test parameters. Brittle erosion behaviour was depicted in erosion testing, and the coatings couldn't restrain the erodent attacks to protect the substrate. High particle velocity and high particle flux were attributed to be the reasons of extensive erosive weight loss of the coatings. The surface morphology of the eroded specimens was analysed from back-scattered electron images to depict the probable mechanism of material removal. The coatings were characterized with optical microscopy, SEM-EDS analysis, XRD analysis, micro-hardness testing, porosity measurements, surface roughness testing and bond strength testing. The work was undertaken to investigate the performance of the selected coatings in highly erosive environment, so as to envisage their application in PCBNs for protection against material degradation. The coatings could only sustain in oblique impact erosion at room temperature and depleted fully under all other conditions.

  2. Erosion rates for polymers measured on LDEF

    Science.gov (United States)

    Gregory, John C.

    1992-01-01

    The summary and viewgraphs of work presented at the Long Duration Exposure Facility (LDEF) materials workshop are given. Experimental data for erosion depths and rates for polymers measured on LDEF are given. In general, agreement is reasonably good between erosion rates from the University of Alabama in Huntsville (UAH) LDEF experiment and prior data obtained at much lower mission fluences. Agreement is particularly satisfying in the case of Kapton where the prior data base is large. In spite of the known presence of silicaceous contamination on LDEF surfaces, the erosion rates of the highly erodible materials are hardly affected, if at all. Graphs showing changes in optical properties (reflectance and transmittance) of metal films are included.

  3. A Study of Cavitation Erosion

    International Nuclear Information System (INIS)

    Hiromu Isaka; Masatsugu Tsutsumi; Tadashi Shiraishi; Hiroyuki Kobayashi

    2002-01-01

    The authors performed experimental study for the purpose of the following two items from a viewpoint of cavitation erosion of a cylindrical orifice in view of a problem at the letdown orifice in PWR (Pressurized Water Reactor). 1. To get the critical cavitation parameter of the cylindrical orifice to establish the design criteria for prevention of cavitation erosion, and 2. to ascertain the erosion rate in such an eventuality that the cavitation erosion occurs with the orifice made of stainless steel with precipitation hardening (17-4-Cu hardening type stainless steel), so that we confirm the appropriateness of the design criteria. Regarding the 1. item, we carried out the cavitation tests to get the critical cavitation parameters inside and downstream of the orifice. The test results showed that the cavitation parameter at inception is independent of the length or the diameter of the orifice. Moreover, the design criteria of cavitation erosion of cylindrical orifices have been established. Regarding the 2. item, we tested the erosion rate under high-pressure conditions. The cavitation erosion actually occurred in the cylindrical orifice at the tests that was strongly resemble to the erosion occurred at the plant. It will be seldom to reproduce resemble cavitation erosion in a cylindrical orifice with the hard material used at plants. We could establish the criteria for preventing the cavitation erosion from the test results. (authors)

  4. The development of U. S. soil erosion prediction and modeling

    Directory of Open Access Journals (Sweden)

    John M. Laflen

    2013-09-01

    Full Text Available Soil erosion prediction technology began over 70 years ago when Austin Zingg published a relationship between soil erosion (by water and land slope and length, followed shortly by a relationship by Dwight Smith that expanded this equation to include conservation practices. But, it was nearly 20 years before this work's expansion resulted in the Universal Soil Loss Equation (USLE, perhaps the foremost achievement in soil erosion prediction in the last century. The USLE has increased in application and complexity, and its usefulness and limitations have led to the development of additional technologies and new science in soil erosion research and prediction. Main among these new technologies is the Water Erosion Prediction Project (WEPP model, which has helped to overcome many of the shortcomings of the USLE, and increased the scale over which erosion by water can be predicted. Areas of application of erosion prediction include almost all land types: urban, rural, cropland, forests, rangeland, and construction sites. Specialty applications of WEPP include prediction of radioactive material movement with soils at a superfund cleanup site, and near real-time daily estimation of soil erosion for the entire state of Iowa.

  5. Development of an Integrated Water and Wind Erosion Model

    Science.gov (United States)

    Flanagan, D. C.; Ascough, J. C.; Wagner, L. E.; Geter, W. F.

    2006-12-01

    Prediction technologies for soil erosion by the forces of wind or water have largely been developed independently from one another, especially within the United States. Much of this has been due to the initial creation of equations and models which were empirical in nature (i.e., Universal Soil Loss Equation, Wind Erosion Equation) and based upon separate water erosion or wind erosion plot and field measurements. Additionally, institutional organizations in place typically divided research efforts and funding to unique wind or water erosion research and modeling projects. However, during the past 20 years computer technologies and erosion modeling have progressed to the point where it is now possible to merge physical process-based computer simulation models into an integrated water and wind erosion prediction system. In a physically- based model, many of the processes which must be simulated for wind and water erosion computations are the same, e.g., climate, water balance, runoff, plant growth, etc. Model components which specifically deal with the wind or water detachment, transport and deposition processes are those that must differ, as well as any necessary parameterization of input variables (e.g., adjusted soil erodibilities, critical shear stresses, etc.) for those components. This presentation describes current efforts towards development of a combined wind and water erosion model, based in part upon technologies present in the Water Erosion Prediction Project (WEPP) and the Wind Erosion Prediction System (WEPS) models. Initial efforts during the past two years have resulted in modular modeling components that allow for prediction of infiltration, surface runoff, and water erosion at a hillslope scale within an Object Modeling System. Additional components currently in development include wind detachment at a single field point, continuous water balance, and unified plant growth. Challenges in this project are many, and include adequate field

  6. Aqueous Corrosion Rates for Waste Package Materials

    Energy Technology Data Exchange (ETDEWEB)

    S. Arthur

    2004-10-08

    The purpose of this analysis, as directed by ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]), is to compile applicable corrosion data from the literature (journal articles, engineering documents, materials handbooks, or standards, and national laboratory reports), evaluate the quality of these data, and use these to perform statistical analyses and distributions for aqueous corrosion rates of waste package materials. The purpose of this report is not to describe the performance of engineered barriers for the TSPA-LA. Instead, the analysis provides simple statistics on aqueous corrosion rates of steels and alloys. These rates are limited by various aqueous parameters such as temperature (up to 100 C), water type (i.e., fresh versus saline), and pH. Corrosion data of materials at pH extremes (below 4 and above 9) are not included in this analysis, as materials commonly display different corrosion behaviors under these conditions. The exception is highly corrosion-resistant materials (Inconel Alloys) for which rate data from corrosion tests at a pH of approximately 3 were included. The waste package materials investigated are those from the long and short 5-DHLW waste packages, 2-MCO/2-DHLW waste package, and the 21-PWR commercial waste package. This analysis also contains rate data for some of the materials present inside the fuel canisters for the following fuel types: U-Mo (Fermi U-10%Mo), MOX (FFTF), Thorium Carbide and Th/U Carbide (Fort Saint Vrain [FSVR]), Th/U Oxide (Shippingport LWBR), U-metal (N Reactor), Intact U-Oxide (Shippingport PWR, Commercial), aluminum-based, and U-Zr-H (TRIGA). Analysis of corrosion rates for Alloy 22, spent nuclear fuel, defense high level waste (DHLW) glass, and Titanium Grade 7 can be found in other analysis or model reports.

  7. Corrosion chemistry closing comments: opportunities in corrosion science facilitated by operando experimental characterization combined with multi-scale computational modelling.

    Science.gov (United States)

    Scully, John R

    2015-01-01

    Recent advances in characterization tools, computational capabilities, and theories have created opportunities for advancement in understanding of solid-fluid interfaces at the nanoscale in corroding metallic systems. The Faraday Discussion on Corrosion Chemistry in 2015 highlighted some of the current needs, gaps and opportunities in corrosion science. Themes were organized into several hierarchical categories that provide an organizational framework for corrosion. Opportunities to develop fundamental physical and chemical data which will enable further progress in thermodynamic and kinetic modelling of corrosion were discussed. These will enable new and better understanding of unit processes that govern corrosion at the nanoscale. Additional topics discussed included scales, films and oxides, fluid-surface and molecular-surface interactions, selected topics in corrosion science and engineering as well as corrosion control. Corrosion science and engineering topics included complex alloy dissolution, local corrosion, and modelling of specific corrosion processes that are made up of collections of temporally and spatially varying unit processes such as oxidation, ion transport, and competitive adsorption. Corrosion control and mitigation topics covered some new insights on coatings and inhibitors. Further advances in operando or in situ experimental characterization strategies at the nanoscale combined with computational modelling will enhance progress in the field, especially if coupling across length and time scales can be achieved incorporating the various phenomena encountered in corrosion. Readers are encouraged to not only to use this ad hoc organizational scheme to guide their immersion into the current opportunities in corrosion chemistry, but also to find value in the information presented in their own ways.

  8. A terminological matter: paragenesis, antigravitative erosion or antigravitational erosion ?

    Directory of Open Access Journals (Sweden)

    Pasini G.

    2009-07-01

    Full Text Available In the speleological literature three terms are utilized to designate the “ascending erosion”: paragenesis (= paragénésis, coined in1968, antigravitative erosion (= erosione antigravitativa, coined in 1966 and antigravitational erosion (wrong English translation ofthe Italian term erosione antigravitativa, utilized later on. The term paragenesis should be abandoned because of the priority of theterm erosione antigravitativa - on the ground of the “law of priority” – and because of its ambiguous etimology. On the other hand,the term antigravitational erosion should be forsaken in favour of the term antigravitative erosion, given the meaning that the termsgravitation and gravity have in Physics. Therefore, to designate the phenomenon of the “ascending erosion” there would be nothingleft but the term antigravitative erosion.The antigravitative erosion process and its recognizability are illustrated.Examples of caves with evident antigravitative erosion phenomena, developed in different karstifiable rocks and in several partsof the world, are given.It is recalled that the antigravitative erosion is a phenomenon well-known since 1942 and widely proven and supported, and that it isrelatively easy – in many cases - to recognize the antigravitative origin of karstic passages.It is stressed that the antigravitative erosion is an important phenomenon, exclusive of the karstic caves and unique in nature.

  9. Eolian erosion of the Martian surface. I - Erosion rate similitude

    Science.gov (United States)

    Iversen, J. D.; White, B. R.; Greeley, R.; Pollack, J. B.

    1975-01-01

    A similitude parameter is derived which is based on theoretical considerations of erosion due to sand in saltation. This parameter has been used to correlate wind tunnel experiments of particle flow over model craters. The characteristics of the flow field in the vicinity and downstream of a crater are discussed and it is shown that erosion is initiated in areas lying under a pair of trailing vortices. The erosion rate parameter is used to calculate erosion rates on Mars, reported in Part 2, to be published later.

  10. Advanced experimental and numerical techniques for cavitation erosion prediction

    CERN Document Server

    Chahine, Georges; Franc, Jean-Pierre; Karimi, Ayat

    2014-01-01

    This book provides a comprehensive treatment of the cavitation erosion phenomenon and state-of-the-art research in the field. It is divided into two parts. Part 1 consists of seven chapters, offering a wide range of computational and experimental approaches to cavitation erosion. It includes a general introduction to cavitation and cavitation erosion, a detailed description of facilities and measurement techniques commonly used in cavitation erosion studies, an extensive presentation of various stages of cavitation damage (including incubation and mass loss), and insights into the contribution of computational methods to the analysis of both fluid and material behavior. The proposed approach is based on a detailed description of impact loads generated by collapsing cavitation bubbles and a physical analysis of the material response to these loads. Part 2 is devoted to a selection of nine papers presented at the International Workshop on Advanced Experimental and Numerical Techniques for Cavitation Erosion (Gr...

  11. Screening of soil corrosivity by field testing: Results and design of an electrochemical soil corrosion probe

    DEFF Research Database (Denmark)

    Nielsen, Lars vendelbo; Bruun, Niels Kåre

    1996-01-01

    The corrosivity of different types of soil have been assessed by exposing carbon-steel plates at 50 different locations in Denmark for an extended period of time. The investigations included weight loss measurements and analysis of the chemical compositions of the corrosion products formed on the...... and hydrogen absorption rates. In addition, traditional carbon-steel 3-electrode arrangements allow for performance of any kind of electrochemical meaurement (EIS, polarisation curves, LPR-measurements, galvanostatic pulse etc.).......The corrosivity of different types of soil have been assessed by exposing carbon-steel plates at 50 different locations in Denmark for an extended period of time. The investigations included weight loss measurements and analysis of the chemical compositions of the corrosion products formed...... on the plates during exposure. An electrochemical soil corrosion probe has been designed and manufactured allowing for simultaneous measurements of several qauntities to predict corrosion. The probe consists of individual sections capable of measuring redox-potential, corrosion potential, soil resistivity...

  12. Corrosion Failures in Marine Environment

    OpenAIRE

    R. Krishnan

    1985-01-01

    This paper gives a brief description of typical marine environments and the most common form of corrosion of materials used in this environment. Some typical case histories of failures pertaining to pitting, bimetallic corrosion, dealloying, cavitation and stress corrosion cracking are illustrated as typical examples of corrosion failures.

  13. Automated Methods Of Corrosion Measurements

    DEFF Research Database (Denmark)

    Bech-Nielsen, Gregers; Andersen, Jens Enevold Thaulov; Reeve, John Ch

    1997-01-01

    The chapter describes the following automated measurements: Corrosion Measurements by Titration, Imaging Corrosion by Scanning Probe Microscopy, Critical Pitting Temperature and Application of the Electrochemical Hydrogen Permeation Cell.......The chapter describes the following automated measurements: Corrosion Measurements by Titration, Imaging Corrosion by Scanning Probe Microscopy, Critical Pitting Temperature and Application of the Electrochemical Hydrogen Permeation Cell....

  14. Microbiologically influenced corrosion of stainless steel in a nuclear waste facility

    International Nuclear Information System (INIS)

    Jenkins, C.F.; Doman, D.L.

    1992-01-01

    Corrosion in stainless steel cooling water piping in a nuclear waste processing facility occurred during an extended system lay-up. The failure characteristics indicated microbiologically influenced corrosion (MIC). The corrosion occurred at welds as pinhole penetrations in the surfaces, which opened into large subsurface void formations. Corrosive attack started in the heat-affected zones of the assembly welds, usually adjacent to fusion lines. Stepwise grinding, polishing, and etching in the affected areas revealed that voids generally grew in the wrought material as uniform, general corrosion. Tunneling (wormholing) erosion was also present. Selective attack occurred within the two-phase weld filler zone. The result was a void wall that was rough and porous-appearing, a consequence of preferential attack on the austenite. The three-dimensional spongy surface was studied optically and with the scanning electron microscope

  15. An electrochemical study of the corrosion behavior of primer coated 2219-T87 aluminum

    Science.gov (United States)

    Danford, M. D.; Higgins, R. H.

    1985-01-01

    The corrosion behavior for 2219-T87 aluminum coated with various primers, including those used for the external tank and solid rocket boosters of the Space Shuttle Transportation System, were investigated using electrochemical techniques. Corrosion potential time, polarization resistance time, electrical resistance time, and corrosion rate time measurements were all investigated. It was found that electrical resistance time and corrosion rate time measurement were most useful for studying the corrosion behavior of painted aluminum. Electrical resistance time determination give useful information concerning the porosity of paint films, while corrosion rate time curves give important information concerning overall corrosion rates and corrosion mechanisms. In general, the corrosion rate time curves all exhibited at least one peak during the 30 day test period, which was attributed, according to the proposed mechanisms, to the onset of the hydrogen evolution reaction and the beginning of destruction of the protective properties of the paint film.

  16. Corrosion in systems for storage and transportation of petroleum products and biofuels identification, monitoring and solutions

    CERN Document Server

    Groysman, Alec

    2014-01-01

    This book treats corrosion as it occurs and affects processes in real-world situations, and thus points the way to practical solutions. Topics described include the conditions in which petroleum products are corrosive to metals; corrosion mechanisms of petroleum products; which parts of storage tanks containing crude oils and petroleum products undergo corrosion; dependence of corrosion in tanks on type of petroleum products; aggressiveness of petroleum products to polymeric material; how microorganisms take part in corrosion of tanks and pipes containing petroleum products; which corrosion monitoring methods are used in systems for storage and transportation of petroleum products; what corrosion control measures should be chosen; how to choose coatings for inner and outer surfaces of tanks containing petroleum products; and how different additives (oxygenates, aromatic solvents) to petroleum products and biofuels influence metallic and polymeric materials. The book is of interest to corrosion engineers, mat...

  17. Paint for detection of corrosion and warning of chemical and radiological attack

    Science.gov (United States)

    Farmer, Joseph C [Tracy, CA

    2010-08-24

    A system for warning of corrosion, chemical, or radiological substances. The system comprises painting a surface with a paint or coating that includes an indicator material and monitoring the surface for indications of the corrosion, chemical, or radiological substances.

  18. Corrosion-resistant uranium

    Science.gov (United States)

    Hovis, Jr., Victor M.; Pullen, William C.; Kollie, Thomas G.; Bell, Richard T.

    1983-01-01

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  19. A corrosion control manual for rail rapid transit

    Science.gov (United States)

    Gilbert, L. O.; Fitzgerald, J. F., II; Menke, J. T.

    1982-01-01

    In 1979, during the planning stage of the Metropolitan Dade County Transit System, the need was expressed for a corrosion control manual oriented to urban rapid transit system use. This manual responds to that need. The objective of the manual is to aid rail rapid transit agencies by providing practical solutions to selected corrosion problems. The scope of the manual encompasses corrosion problems of the facilities of rapid transit systems: structures and tracks, platforms and stations, power and signals, and cars. It also discusses stray electric current corrosion. Both design and maintenance solutions are provided for each problem. Also included are descriptions of the types of corrosion and their causes, descriptions of rapid transit properties, a list of corrosion control committees and NASA, DOD, and ASTM specifications and design criteria to which reference is made in the manual. A bibliography of papers and excerpts of reports and a glossary of frequency used terms are provided.

  20. Shoulder erosions in renal osteodystrophy

    International Nuclear Information System (INIS)

    Bonavita, J.A.; Dalinka, M.K.

    1980-01-01

    The radiographic manifestations of renal osteodystrophy may be articular as well as osseous. The latter are well recognized, i.e. subperiosteal and subchondral bony resorption. Recently attention has been directed to the occurrence of an erosive arthritis of the hands and wrists in hyperparathyroidism. The authors present six patients with humeral head erosions, all of whom were on chronic long-term hemodialysis. These intra-articular erosions occurred at the 'bare' area of the humeral head and thus represent an erosive arthritis and therefore can be distinguished from the usual sites of subchondral and subperiosteal bony resorption seen in hyperparathyroidism. (orig.) [de

  1. Multiperspective analysis of erosion tolerance

    Directory of Open Access Journals (Sweden)

    Sparovek Gerd

    2003-01-01

    Full Text Available Erosion tolerance is the most multidisciplinary field of soil erosion research. Scientists have shown lack in ability to adequately analyze the huge list of variables that influence soil loss tolerance definitions. For these the perspectives of erosion made by farmers, environmentalists, society and politicians have to be considered simultaneously. Partial and biased definitions of erosion tolerance may explain not only the polemic nature of the currently suggested values but also, in part, the nonadoption of the desired levels of erosion control. To move towards a solution, considerable changes would have to occur on how this topic is investigated, especially among scientists, who would have to change methods and strategies and extend the perspective of research out of the boundaries of the physical processes and the frontiers of the academy. A more effective integration and communication with the society and farmers, to learn about their perspective of erosion and a multidisciplinary approach, integrating soil, social, economic and environmental sciences are essential for improved erosion tolerance definitions. In the opinion of the authors, soil erosion research is not moving in this direction and a better understanding of erosion tolerance is not to be expected in the near future.

  2. Study on pipe wastage mechanism by liquid droplet impingement erosion

    International Nuclear Information System (INIS)

    Higashi, Yuma; Narabayashi, Tadashi; Shimazu, Yoichiro; Tsuji, Masashi; Ohmori, Shuichi; Mori, Michitsugu; Tezuka, Kenichi

    2009-01-01

    Evaluation of wastage speed for nuclear power plant maintains plant reliability and power up rating is important. There are two main cause of wastage flow accelerated corrosion (FAC) and mechanical erosion. This study is to develop evaluating the wastage speed by liquid droplet impingement erosion (LDIE). LDIE often occurs at downstream of corner of pipe or orifice. In this study, the liquid drop impinging tests were conducted with the test pieces mounted on a high speed rotating disk that cross thin water down jet and produced LDIE phenomena. The amount of the wastage by LDIE was evaluated by changing the rotational speed, the impingement frequency, and test piece materials. In addition, the generation mechanism of erosion was investigated by observing the surface of the test piece with a microscope. There is a method of evaluating by the mass difference before and after experiments. But this method is not correct because error becomes larger for mass measurement in the experiment, for the lost mass by LDIE is very little amount. Therefore, the method was developed to measure the volume in the erosion part. In this method, depth of LDIE was measured by the accuracy of ±0.01μm; therefore accurate measurement of the wastage can be improved. (author)

  3. Erosion of buffer caused by groundwater leakages

    International Nuclear Information System (INIS)

    Autio, J.; Hanana, K.; Punkkinen, O.; Koskinen, K.; Olin, M.

    2010-01-01

    Document available in extended abstract form only. In the Finnish HLW disposal concept the most important properties of the bentonite clay being considered for these isolation purposes are its thermal behaviour, low hydraulic conductivity, diffusion limited transport, rheology, plasticity, sufficient swelling potential, and exchange capacity. All of these properties depend critically on bentonite density; therefore, any potential mass loss or redistribution events must be well characterized. One such event or process is the erosion of bentonite by flowing groundwater and the groundwater flowing in newly formed channels, in special. Mechanical erosion during the operational phase, due to high groundwater pressure gradients in open excavations, has been identified as a critical issue in TKS-2006 and SR-Can. This work addresses the mechanical erosion of bentonite by fluid shear. In order for buffer erosion to occur three processes must take place: detachment, entrainment, and transport. These processes are followed by the settling of the material and redistribution of buffer mass. Erosion begins with the detachment of a particle from surrounding material, which requires the application of shear forces greater than the attractive force between the particle and parent structure. Entrainment is the process by which the eroding medium lifts the detached particle into the flow. The most important aspect in entrainment is transfer of fluid's inertial forces via surface friction to particles' inertial forces, which, in turn, must overcome the frictional resistance between the particle and its surroundings. Factors influencing frictional resistance include gravity, particle mass, saturation degree of parent structure, composition of water present in parent structure, particle size, and surface roughness. Recent erosion tests, whereby water flow was directed over compacted bentonite blocks or through a system of bentonite pellets, have indicated that bentonite erodes

  4. Plasma erosion switch

    International Nuclear Information System (INIS)

    Mendel, C.W. Jr.; Goldstein, S.A.; Miller, P.A.

    1976-01-01

    The plasma erosion switch is a device capable of initially carrying high currents, and then of opening in nanoseconds to stand off high voltages. It depends upon the erosion of a plasma which initially fills the switch. The sheath between the plasma and the cathode behaves as a diode with a rapidly increasing A-K gap. Preliminary tests of the switch on the Proto I accelerator at Sandia will be described. In these tests, the switch consisted of a cylinder of highly ionized plasma four inches in diameter and one-inch thick surrounding a one-inch cathode. The switch shorted out prepulse voltages and allowed energy to be stored in the diode inductance outside the switch until the accelerator current reached 75 kA. The switch impedance then rose rapidly to approximately 100 ω in 5 nanoseconds, whereupon the accelerator current transferred to the cathode. Current rise rates of 3.10 13 A/sec were limited by cathode turn-on. Voltage rise rates of 10 15 V/sec were achieved. The elimination of prepulse and machine turn-on transients allowed A-K gaps of 2 mm to be used with 2.5 MV pulses, yielding average E fields of 12 MV/cm. Staged versions of the device are being built and should improve rise rates. The switch shows promise for use with future, higher power, lower inductance machines

  5. Erosion in extruder flow

    Science.gov (United States)

    Kaufman, Miron; Fodor, Petru S.

    A detailed analysis of the fluid flow in Tadmor's unwound channel model of the single screw extruder is performed by combining numerical and analytical methods. Using the analytical solution for the longitudinal velocity field (in the limit of zero Reynolds number) allows us to devote all the computational resources solely for a detailed numerical solution of the transversal velocity field. This high resolution 3D model of the fluid flow in a single-screw extruder allows us to identify the position and extent of Moffatt eddies that impede mixing. We further consider the erosion of particles (e.g. carbon-black agglomerates) advected by the polymeric flow. We assume a particle to be made of primary fragments bound together. In the erosion process a primary fragment breaks out of a given particle. Particles are advected by the laminar flow and they disperse because of the shear stresses imparted by the fluid. The time evolution of the numbers of particles of different sizes is described by the Bateman coupled differential equations used to model radioactivity. Using the particle size distribution we compute an entropic fragmentation index which varies from 0 for a monodisperse system to 1 for an extreme poly-disperse system.

  6. Methods and apparatus for managing corrosion in buildings

    Science.gov (United States)

    Chey, S Jay; Hamann, Hendrik F; Klein, Levente Ioan; Schappert, Michael Alan; Stepanchuk, Andriy

    2015-02-03

    Principles of the invention provide methods and apparatus for providing corrosion management in buildings. In one aspect, an exemplary method includes the step of receiving first data relating corrosion rate to a plurality of environmental conditions. This first data is subsequently utilized to determine a quantitative relationship between corrosion rate and the plurality of environmental conditions. In another step, second data indicative of one or more environmental conditions within a building is received. A corrosion rate in the building is then determined at least in part by applying the determined quantitative relationship to this second data.

  7. Erosion mechanism and erosion products in carbon-based materials

    Energy Technology Data Exchange (ETDEWEB)

    Arkhipov, N.; Bakhtin, V.; Barsuk, V.; Kurkin, S.; Mironova, E.; Piazza, G.; Safronov, V. E-mail: vsafr@rico.ttk.ru; Scaffidi-Argentina, F.; Toporkov, D.; Vasenin, S.; Wuerz, H.; Zhitlukhin, A

    2002-12-01

    Plasma/material interaction was studied in disruption simulation experiments at the plasma gun facility MK-200. Graphite and carbon-fibre composites were exposed to pulsed energetic plasma under heat loads typically expected for disruptions in future tokamaks. Erosion rates, erosion mechanisms and the properties of the eroded carbon have been studied.

  8. Do erosion control and snakes mesh?

    Science.gov (United States)

    Christopher Barton; Karen Kinkead

    2005-01-01

    In the battle to curb soil erosion and sedimentation, numberous techniques and products for controlling erosion and sedimentation have been developed and are being implemented. Rolled erosion control products, such as a temporary erosion control blankets and permanent turf reinforcement mats, represent one type of erosion control product that has been used extensively...

  9. Rill erosion rates in burned forests

    Science.gov (United States)

    Joseph W. Wagenbrenner; Peter R. Robichaud

    2011-01-01

    Introduction Wildfires often produce large increases in runoff and erosion rates (e.g., Moody and Martin, 2009), and land managers need to predict the frequency and magnitude of postfire erosion to determine the needs for hazard response and possible erosion mitigation to reduce the impacts of increased erosion on public safety and valued resources. The Water Erosion...

  10. Development of protocols for corrosion and deposits evaluation in pipes by radiography

    International Nuclear Information System (INIS)

    2005-04-01

    The International Atomic Energy Agency is promoting industrial applications of non-destructive testing (NDT) technology, which includes radiography testing (RT) and related methods, to assure safety and reliability of operation of nuclear, petrochemical and other industrial facilities. In many industries such as petroleum, power stations, refineries, petrochemical and chemical plants, desalination pipelines and urban gas installations, the reliability and safety of equipment can be substantially influenced by degradation processes such as corrosion, erosion, deposits and blocking of pipes, which can seriously affect the security and consistency. One of the most important parameters in a piping or pipeline to be monitored and measured is the wall thickness. Among NDT methods, radiography has the advantage in that in the process of an inspection it eliminates the need for the costly removal of the pipe insulation and also the added benefit that it can be carried out in high temperature environments. The Coordinated Research Project (CRP) on Validation of Protocols for Corrosion and Deposits Determination in Small Diameter Pipes by Radiography (CORDEP) was implemented from 1997 to 2000 with the participation of 11 NDT laboratories from Algeria, China, Costa Rica, France, India, Republic of Korea, Malaysia, Sri Lanka, Syrian Arab Republic, Tunisia and Turkey. The CRP tested and validated radiographic measurement of corrosion and deposits in straight and bent pipes made of carbon or stainless steels corroded/eroded on the outer or inner surfaces with or without insulation. Each participating laboratory produced three test specimens of straight and bent pipes containing natural as well as simulated corrosion defects. Typical diameters of these pipes were up to 168 mm. Radiography using X ray machines and radioisotopes of Iridium-192 and Cobalt-60 in conjunction with radiographic film using single and double wall penetrations for total inspection was performed. Selected

  11. BWR steel containment corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Tan, C.P.; Bagchi, G.

    1996-04-01

    The report describes regulatory actions taken after corrosion was discovered in the drywell at the Oyster Creek Plant and in the torus at the Nine Mile Point 1 Plant. The report describes the causes of corrosion, requirements for monitoring corrosion, and measures to mitigate the corrosive environment for the two plants. The report describes the issuances of generic letters and information notices either to collect information to determine whether the problem is generic or to alert the licensees of similar plants about the existence of such a problem. Implementation of measures to enhance the containment performance under severe accident conditions is discussed. A study by Brookhaven National Laboratory (BNL) of the performance of a degraded containment under severe accident conditions is summarized. The details of the BNL study are in the appendix to the report.

  12. Corrosion Inhibitors for Aluminum.

    Science.gov (United States)

    Muller, Bodo

    1995-01-01

    Describes a simple and reliable test method used to investigate the corrosion-inhibiting effects of various chelating agents on aluminum pigments in aqueous alkaline media. The experiments that are presented require no complicated or expensive electronic equipment. (DDR)

  13. Corrosion of valve metals

    International Nuclear Information System (INIS)

    Draley, J.E.

    1976-01-01

    A general survey related to the corrosion of valve metals or film-forming metals. The way these metals corrode with some general examples is described. Valve metals form relatively perfect oxide films with little breakdown or leakage when anodized

  14. Synergism in materials erosion due to multispecies impact

    International Nuclear Information System (INIS)

    Auciello, O.; Haasz, A.A.; Stangeby, P.C.

    1985-01-01

    Microelectronic fabrication often involves the use of relatively low-pressure/low-temperature plasma discharges for etching micron-size features in integrated circuits: here erosion is a desired effect. Fusion plasmas, by contrast, cause erosion of the fusion device inner walls, which is generally not desirable. In both cases surfaces are bombarded simultaneously by plasma species which include ions, neutral atoms, electrons and photons, which might lead to enhanced erosion due to synergistic effects. Work performed to date suggests that similar chemistry may be involved in the erosion process associated with some semiconductor and fusion related materials: SiF 4 , SiCl 4 and CH 4 , are, for example,some of the principal species evolving from Si and C surfaces, when exposed to F, Cl and H atoms respectively, causing the observed erosion. Considerable effort has been expended on studies involving synergistic effects for semiconductor fabrication. Research on synergism related to the erosion of fusion materials (C and carbon compounds) commenced comparatively recently; however, its importance has been increasingly recognized and evidence of possible synergistic erosion of graphite has recently been obtained in the PLT fusion device. Experimental and theoretical work on synergistic effects in erosion of both semiconductors and fusion materials will be critically reviewed. (author)

  15. Galvanic corrosion of beryllium welds

    International Nuclear Information System (INIS)

    Hill, M.A.; Butt, D.P.; Lillard, R.S.

    1997-01-01

    Beryllium is difficult to weld because it is highly susceptible to cracking. The most commonly used filler metal in beryllium welds is Al-12 wt.% Si. Beryllium has been successfully welded using Al-Si filler metal with more than 30 wt.% Al. This filler creates an aluminum-rich fusion zone with a low melting point that tends to backfill cracks. Drawbacks to adding a filler metal include a reduction in service temperature, a lowering of the tensile strength of the weld, and the possibility for galvanic corrosion to occur at the weld. To evaluate the degree of interaction between Be and Al-Si in an actual weld, sections from a mock beryllium weldment were exposed to 0.1 M Cl - solution. Results indicate that the galvanic couple between Be and the Al-Si weld material results in the cathodic protection of the weld and of the anodic dissolution of the bulk Be material. While the cathodic protection of Al is generally inefficient, the high anodic dissolution rate of the bulk Be during pitting corrosion combined with the insulating properties of the Be oxide afford some protection of the Al-Si weld material. Although dissolution of the Be precipitate in the weld material does occur, no corrosion of the Al-Si matrix was observed

  16. Chemical cleaning, decontamination and corrosion

    International Nuclear Information System (INIS)

    Gadiyar, H.S.; Das Chintamani; Gaonkar, K.B.

    1991-01-01

    Chemical cleaning of process equipments and pipings in chemical/petrochemical industries is necessitated for improving operation, for preventing premature failures and for avoiding contamination. In developing a chemical formulation for cleaning equipments, the important aspects to be considered include (i) effective removal of corrosion products and scales, (ii) minimum corrosion of the base metal, (iii) easy to handle chemicals and (iv) economic viability. As on date, a wide variety of chemical formulations are available, many of them are either proprietory or patented. For evolving an effective formulation, knowledge of the oxides of various metals and alloys on the one hand and acid concentration, complexing agents and inhibitors to be incorporated on the other, is quite essential. Organic acids like citric acid, acetic acid and formic acid are more popular ones, often used with EDTA for effective removal of corrosion products from ferrous components. The report enumerates some of the concepts in developing effective formulations for chemical cleaning of carbon steel components and further, makes an attempt to suggest simple formulations to be developed for chemical decontamination. (author). 6 refs., 3 fi gs., 4 tabs

  17. Scaling up from field to region for wind erosion prediction using a field-scale wind erosion model and GIS

    Science.gov (United States)

    Zobeck, T.M.; Parker, N.C.; Haskell, S.; Guoding, K.

    2000-01-01

    Factors that affect wind erosion such as surface vegetative and other cover, soil properties and surface roughness usually change spatially and temporally at the field-scale to produce important field-scale variations in wind erosion. Accurate estimation of wind erosion when scaling up from fields to regions, while maintaining meaningful field-scale process details, remains a challenge. The objectives of this study were to evaluate the feasibility of using a field-scale wind erosion model with a geographic information system (GIS) to scale up to regional levels and to quantify the differences in wind erosion estimates produced by different scales of soil mapping used as a data layer in the model. A GIS was used in combination with the revised wind erosion equation (RWEQ), a field-scale wind erosion model, to estimate wind erosion for two 50 km2 areas. Landsat Thematic Mapper satellite imagery from 1993 with 30 m resolution was used as a base map. The GIS database layers included land use, soils, and other features such as roads. The major land use was agricultural fields. Data on 1993 crop management for selected fields of each crop type were collected from local government agency offices and used to 'train' the computer to classify land areas by crop and type of irrigation (agroecosystem) using commercially available software. The land area of the agricultural land uses was overestimated by 6.5% in one region (Lubbock County, TX, USA) and underestimated by about 21% in an adjacent region (Terry County, TX, USA). The total estimated wind erosion potential for Terry County was about four times that estimated for adjacent Lubbock County. The difference in potential erosion among the counties was attributed to regional differences in surface soil texture. In a comparison of different soil map scales in Terry County, the generalised soil map had over 20% more of the land area and over 15% greater erosion potential in loamy sand soils than did the detailed soil map. As

  18. Prediction of Corrosion of Advanced Materials and Fabricated Components

    Energy Technology Data Exchange (ETDEWEB)

    A. Anderko; G. Engelhardt; M.M. Lencka (OLI Systems Inc.); M.A. Jakab; G. Tormoen; N. Sridhar (Southwest Research Institute)

    2007-09-29

    The goal of this project is to provide materials engineers, chemical engineers and plant operators with a software tool that will enable them to predict localized corrosion of process equipment including fabricated components as well as base alloys. For design and revamp purposes, the software predicts the occurrence of localized corrosion as a function of environment chemistry and assists the user in selecting the optimum alloy for a given environment. For the operation of existing plants, the software enables the users to predict the remaining life of equipment and help in scheduling maintenance activities. This project combined fundamental understanding of mechanisms of corrosion with focused experimental results to predict the corrosion of advanced, base or fabricated, alloys in real-world environments encountered in the chemical industry. At the heart of this approach is the development of models that predict the fundamental parameters that control the occurrence of localized corrosion as a function of environmental conditions and alloy composition. The fundamental parameters that dictate the occurrence of localized corrosion are the corrosion and repassivation potentials. The program team, OLI Systems and Southwest Research Institute, has developed theoretical models for these parameters. These theoretical models have been applied to predict the occurrence of localized corrosion of base materials and heat-treated components in a variety of environments containing aggressive and non-aggressive species. As a result of this project, a comprehensive model has been established and extensively verified for predicting the occurrence of localized corrosion as a function of environment chemistry and temperature by calculating the corrosion and repassivation potentials.To support and calibrate the model, an experimental database has been developed to elucidate (1) the effects of various inhibiting species as well as aggressive species on localized corrosion of nickel

  19. Monitoring corrosion rates and localised corrosion in low conductivity water

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2006-01-01

    Monitoring of low corrosion rates and localised corrosion in a media with low conductivity is a challenge. In municipal district heating, quality control may be improved by implementing on-line corrosion monitoring if a suitable technique can be identified to measure both uniform and localised...... corrosion. Electrochemical techniques (LPR, EIS, crevice corrosion current) as well as direct measurement techniques (high-sensitive electrical resistance, weight loss) have been applied in operating plants. Changes in the corrosion processes are best monitored in non-aggressive, low conductivity media...

  20. Rainfall erosivity: An historical review

    Science.gov (United States)

    Rainfall erosivity is the capability of rainfall to cause soil loss from hillslopes by water. Modern definitions of rainfall erosivity began with the development of the Universal Soil Loss Equation (USLE), where rainfall characteristics were statistically related to soil loss from thousands of plot...

  1. Corrosion and anticorrosion. Industrial practice

    International Nuclear Information System (INIS)

    Beranger, G.; Mazille, H.

    2002-01-01

    This book comprises 14 chapters written with the collaboration of about 50 French experts of corrosion. It is complementary to another volume entitled 'corrosion of metals and alloys' and published by the same editor. This volume comprises two parts: part 1 presents the basic notions of corrosion phenomena, the properties of surfaces, the electrochemical properties of corrosion etc.. Part 2 describes the most frequent forms of corrosion encountered in industrial environments and corresponding to specific problems of protection: marine environment, atmospheric corrosion, galvanic corrosion, tribo-corrosion, stress corrosion etc.. The first 8 chapters (part 1) treat of the corrosion problems encountered in different industries and processes: oil and gas production, chemical industry, phosphoric acid industry, PWR-type power plants, corrosion of automobile vehicles, civil engineering and buildings, corrosion of biomaterials, non-destructive testing for the monitoring of corrosion. The other chapters (part 2) deal with anticorrosion and protective coatings and means: choice of materials, coatings and surface treatments, thick organic coatings and enamels, paints, corrosion inhibitors and cathodic protection. (J.S.)

  2. Corrosion penetration monitoring of advanced ceramics in hot aqueous fluids

    Directory of Open Access Journals (Sweden)

    Klaus G. Nickel

    2004-03-01

    Full Text Available Advanced ceramics are considered as components in energy related systems, because they are known to be strong, wear and corrosion resistant in many environments, even at temperatures well exceeding 1000 °C. However, the presence of additives or impurities in important ceramics, for example those based on Silicon Nitride (Si3N4 or Al2O3 makes them vulnerable to the corrosion by hot aqueous fluids. The temperatures in this type of corrosion range from several tens of centigrade to hydrothermal conditions above 100 °C. The corrosion processes in such media depend on both pH and temperature and include often partial leaching of the ceramics, which cannot be monitored easily by classical gravimetric or electrochemical methods. Successful corrosion penetration depth monitoring by polarized reflected light optical microscopy (color changes, Micro Raman Spectroscopy (luminescence changes and SEM (porosity changes will be outlined. The corrosion process and its kinetics are monitored best by microanalysis of cross sections, Raman spectroscopy and eluate chemistry changes in addition to mass changes. Direct cross-calibrations between corrosion penetration and mechanical strength is only possible for severe corrosion. The methods outlined should be applicable to any ceramics corrosion process with partial leaching by fluids, melts or slags.

  3. Corrosion aspects of steel radioactive waste containers in cementitious materials

    International Nuclear Information System (INIS)

    Smart, Nick

    2012-01-01

    Nick Smart from Serco, UK, gave an overview of the effects of cementitious materials on the corrosion of steel during storage and disposal of various low- and intermediate-level radioactive wastes. Steel containers are often used as an overpack for the containment of radioactive wastes and are routinely stored in an open atmosphere. Since this is an aerobic and typically humid environment, the steel containers can start to corrode whilst in storage. Steel containers often come into contact with cementitious materials (e.g. grout encapsulants, backfill). An extensive account of different steel container designs and of steel corrosion mechanisms was provided. Steel corrosion rates under conditions buffered by cementitious materials have been evaluated experimentally. The main conclusion was that the cementitious environment generally facilitates the passivation of steel materials. Several general and localised corrosion mechanisms need to be considered when evaluating the performance of steel containers in cementitious environments, and environmental thresholds can be defined and used with this aim. In addition, the consequences of the generation of gaseous hydrogen by the corrosion of carbon steel under anoxic conditions must be taken into account. Discussion of the paper included: Is crevice corrosion really significant in cementitious systems? Crevice corrosion is unlikely in the cementitious backfill considered because it will tend to neutralise any acidic conditions in the crevice. What is the role of microbially-induced corrosion (MIC) in cementitious systems? Microbes are likely to be present in a disposal facility but their effect on corrosion is uncertain

  4. An overview of materials degradation by stress corrosion in PWRs

    International Nuclear Information System (INIS)

    Scott, P. M.

    2004-01-01

    The aging of water cooled and moderated nuclear steam supply systems has given rise to many material corrosion problems of which stress corrosion cracking has proved to be one of the most serious. The aim of this paper is to review some examples of corrosion and particularly stress corrosion problems from the author's experience of interpreting and modelling these phenomena in PWR systems. Examples of stress corrosion cracking in PWR systems described include the major issue of Alloy 600 intergranular cracking in primary PWR coolants, for which it is generally perceived that both adequate life prediction models and remedial measures now exist. Intergranular corrosion and stress corrosion cracking of Alloy 600 steam generator tubes that occur in occluded superheated crevices on the secondary side of steam generators due to hide-out and concentration of water borne impurities are also addressed. Rather less extensive or well known examples are discussed such as the stress corrosion cracking of carbon and low alloy steels and of stainless steels in occluded dead-leg situations where it is sometimes difficult to guarantee adequate control of water chemistry, particularly at plant start-up. Reference is also be made to the use of high strength fastener materials in PWR systems as well as to the emerging issue of the effect of high neutron doses on the stress corrosion resistance of core structural components fabricated from austenitic stainless steels. (authors)

  5. Corrosion protection of steel in ammonia/water heat pumps

    Science.gov (United States)

    Mansfeld, Florian B.; Sun, Zhaoli

    2003-10-14

    Corrosion of steel surfaces in a heat pump is inhibited by adding a rare earth metal salt to the heat pump's ammonia/water working fluid. In preferred embodiments, the rare earth metal salt includes cerium, and the steel surfaces are cerated to enhance the corrosion-inhibiting effects.

  6. Corrosion resistance of a copper canister for spent nuclear fuel

    International Nuclear Information System (INIS)

    1983-04-01

    The report presents an evaluation of copper as canister material for spent nuclear fuel. The evaluation is made from the viewpoint of corrosion and applies to a concept of 1977. Supplementary corrosion studies have been performed. The report includes 9 appendices which deal with experimental data. (G.B.)

  7. Coaxial stub resonator for online monitoring early stages of corrosion

    NARCIS (Netherlands)

    Hoog-Antonyuk, N.A.; Mayer, Mateo J.J.; Miedema, Henk; Olthuis, Wouter; van den Berg, Albert

    2014-01-01

    Here we demonstrate the proof-of-principle of a new type of flow-through sensor to assess the corrosion rate of metal surfaces. The method can be applied to all situations where metals are exposed to a corrosive (fluidic) environment, including, for instance, the interior of pipes and tubes. Our

  8. Corrosion inhibitors for solar heating and cooling systems

    Science.gov (United States)

    Tabony, J. H.

    1978-01-01

    Candidate materials were tested for their ability to limit corrosion under conditions that approximate those found in typical solar-energy system. In addition to presentation of data, report also includes discussion of different forms of corrosion and recommendations for future work.

  9. Low toxic corrosion inhibitors for aluminum in fresh water

    Science.gov (United States)

    Humphries, T. S.

    1978-01-01

    Combinations of chemical compounds that reportedly reduce the corrosion of aluminum in fresh water were evaluated. These included combinations of borates, nitrates, nitrites, phosphates, silicates, and mercaptobenzothiazole. Eight of fifty inhibitor combinations evaluated gave excellent corrosion protection and compared favorably with sodium chromate, which has generally been considered standard for many years.

  10. Characterizing soil erosion potential using electrical resistivity imaging : final report.

    Science.gov (United States)

    2017-04-01

    The erosion rate, or erodibility, of soil depends on many soil characteristics including: plasticity, : water content, grain size, percent clay, compaction, and shear strength. Many of these characteristics also : influence soil in situ bulk electric...

  11. Characterizing soil erosion potential using electrical resistivity imaging : technical summary.

    Science.gov (United States)

    2017-04-01

    The erosion rate, or erodibility, of soil depends on many soil characteristics : including: plasticity, water content, grain size, percent clay, compaction, and shear : strength. Many of these characteristics also influence soil in situ bulk electric...

  12. Modelling dune erosion, overwash and inundation of barrier islands

    NARCIS (Netherlands)

    Hoonhout, B.; Thiel de Vries, J.S.M.

    2012-01-01

    Physical model experiments are performed at Deltares to investigate the morphological response of barrier islands on extreme storm events. The experiments included dune erosion, overwash and inundation regimes. Extensive measurement techniques made detailed comparison with numerical models possible.

  13. Waterside corrosion of zirconium alloys in nuclear power plants

    International Nuclear Information System (INIS)

    1998-01-01

    Technically the study of corrosion of zirconium alloys in nuclear power reactors is a very active field and both experimental work and understanding of the mechanisms involved are going through rapid changes. As a result, the lifetime of any publication in this area is short. Because of this it has been decided to revise IAEA-TECDOC-684 - Corrosion of Zirconium Alloys in Nuclear Power Plants - published in 1993. This updated, revised and enlarged version includes major changes to incorporate some of the comments received about the first version. Since this review deals exclusively with the corrosion of zirconium and zirconium based alloys in water, and another separate publication is planned to deal with the fuel-side corrosion of zirconium based fuel cladding alloys, i.e. stress corrosion cracking, it was decided to change the original title to Waterside Corrosion of Zirconium Alloys in Nuclear Power Plants. The rapid changes in the field have again necessitated a cut-off date for incorporating new data. This edition incorporates data up to the end of 1995; including results presented at the 11 International Symposium on Zirconium in the Nuclear Industry held in Garmisch-Partenkirchen, Germany, in September 1995. The revised format of the review now includes: Introductory chapters on basic zirconium metallurgy and oxidation theory; A revised chapter discussing the present extent of our knowledge of the corrosion mechanism based on laboratory experiments; a separate and revised chapter discussing hydrogen uptake; a completely reorganized chapter summarizing the phenomenological observations of zirconium alloy corrosion in reactors; a new chapter on modelling in-reactor corrosion; a revised chapter devoted exclusively to the manner in which irradiation might influence the corrosion process; finally, a summary of our present understanding of the corrosion mechanisms operating in reactor

  14. Using REE tracers to measure sheet erosion changing to rill erosion

    International Nuclear Information System (INIS)

    Liu Puling; Xue Yazhou; Song Wei; Wang Mingyi; Ju Tongjun

    2004-01-01

    Rare Earth Elements (REE) tracer method was used to study sheet erosion changing to rill erosion on slope land. By placing different rare earth elements of different soil depth across a slope in an indoor plot, two simulated rainfalls were applied to study the change of erosion type and the rill erosion process. The results indicate that the main erosion type is sheet erosion at the beginning of the rainfalls, and serious erosion happens after rill erosion appears. Accumulated sheet and rill erosion amounts increase with the rainfalls time. The percentage of sheet erosion amount decreases and rill erosion percentage increases with time. At the end of the rainfalls, the total rill erosion amounts are 4-5 times more than sheet erosion. In this paper, a new REE tracer method was used to quantitatively distinguish sheet and rill erosion amounts. The new REE tracer method should be useful to future studying of erosion processes on slope lands. (authors)

  15. Fastener Corrosion: A Result of Moisture Problems in the Building Envelope

    Science.gov (United States)

    Samuel L. Zelinka

    2013-01-01

    This paper reviews recent literature on the corrosion of metals embedded in wood and highlights the link be-tween moisture accumulation in wood and fastener cor-rosion. Mechanisms of fastener corrosion are described including dependence upon wood moisture content. These fundamental concepts are applied to practical examples by explaining how hygrothermal models can be...

  16. Evaluating the new soil erosion map of Hungary

    Science.gov (United States)

    Waltner, István; Centeri, Csaba; Takács, Katalin; Pirkó, Béla; Koós, Sándor; László, Péter; Pásztor, László

    2017-04-01

    With growing concerns on the effects of climate change and land use practices on our soil resources, soil erosion by water is becoming a significant issue internationally. Since the 1964 publication of the first soil erosion map of Hungary, there have been several attempts to provide a countrywide assessment of erosion susceptibility. However, there has been no up-to-date map produced in the last decade. In 2016, a new, 1:100 000 scale soil erosion map was published, based on available soil, elevation, land use and meteorological data for the extremely wet year of 2010. The map utilized combined outputs for two spatially explicit methods: the widely used empirical Universal Soil Loss Equation (USLE) and the process-based Pan-European Soil Erosion Risk Assessment (PESERA) models. The present study aims to provide a detailed analysis of the model results. In lieu of available national monitoring data, information from other sources were used. The Soil Degradation Subsystem (TDR) of the National Environmental Information System (OKIR) is a digital database based on a soil survey and farm dairy data collected from representative farms in Hungary. During the survey all kind of degradation forms - including soil erosion - were considered. Agricultural and demographic data was obtained from the Hungarian Central Statistical Office (KSH). Data from an interview-based survey was also used in an attempt to assess public awareness of soil erosion risks. Point-based evaluation of the model results was complemented with cross-regional assessment of soil erosion estimates. This, combined with available demographic information provides us with an opportunity to address soil erosion on a community level, with the identification of regions with the highest risk of being affected by soil erosion.

  17. Comparison of methods for calculating water erosion

    OpenAIRE

    SVOBODOVÁ, Pavlína

    2011-01-01

    Bachelor thesis presents a comparison of methods for calculating water erosion. The aim is to summarize available evidence concerning the problems of water erosion. There are presented some methods how to calculate average annual erosion of soils, and selected models for calculating the erosion immediately. There are also listed possible erosion control measures through which we can at least slow the effects of erosion, rather than stop completely.

  18. A mechanistic model for predicting flow-assisted and general corrosion of carbon steel in reactor primary coolants

    International Nuclear Information System (INIS)

    Lister, D.

    2002-01-01

    Flow-assisted corrosion (FAC) of carbon steel in high-temperature lithiated water can be described with a model that invokes dissolution of the protective oxide film and erosion of oxide particles that are loosened as a result. General corrosion under coolant conditions where oxide is not dissolved is described as well. In the model, the electrochemistry of magnetite dissolution and precipitation and the effect of particle size on solubility move the dependence on film thickness of the diffusion processes (and therefore the corrosion rate) away from reciprocal. Particle erosion under dissolving conditions is treated stochastically and depends upon the fluid shear stress at the surface. The corrosion rate dependence on coolant flow under FAC conditions then becomes somewhat less than that arising purely from fluid shear (proportional to the velocity squared). Under non-dissolving conditions, particle erosion occurs infrequently and general corrosion is almost unaffected by flow For application to a CANDU primary circuit and its feeders, the model was bench-marked against the outlet feeder S08 removed from the Point Lepreau reactor, which furnished one value of film thickness and one of corrosion rate for a computed average coolant velocity. Several constants and parameters in the model had to be assumed or were optimised, since values for them were not available. These uncertainties are no doubt responsible for the rather high values of potential that evolved as steps in the computation. The model predicts film thickness development and corrosion rate for the whole range of coolant velocities in outlet feeders very well. In particular, the detailed modelling of FAC in the complex geometry of one outlet feeder (F11) is in good agreement with measurements. When the particle erosion computations are inserted in the balance equations for the circuit, realistic values of crud level are obtained. The model also predicts low corrosion rates and thick oxide films for inlet

  19. Plasma Sprayed Bondable Stainless Surface (BOSS) Coatings for Corrosion Protection and Adhesion Treatments

    Science.gov (United States)

    Davis, G. D.; Groff, G. B.; Rooney, M.; Cooke, A. V.; Boothe, R.

    1995-01-01

    Plasma-sprayed Bondable Stainless Surface (BOSS) coatings are being developed under the Solid Propulsion Integrity Program's (SPIP) Bondlines Package. These coatings are designed as a steel case preparation treatment prior to insulation lay-up. Other uses include the exterior of steel cases and bonding surfaces of nozzle components. They provide excellent bondability - rubber insulation and epoxy bonds fail cohesively within the polymer - for both fresh surfaces and surfaces having undergone natural and accelerated environmental aging. They have passed the MSFC requirements for protection of inland and sea coast environment. Because BOSS coatings are inherently corrosion resistant, they do not require preservation by greases or oils. The reduction/elimination of greases and oils, known bondline degraders, can increase SRM reliability, decrease costs by reducing the number of process steps, and decrease environmental pollution by reducing the amount of methyl chloroform used for degreasing and thus reduce release of the ozone-depleting chemical in accordance with the Clean Air Act and the Montreal Protocol. The coatings can potential extend the life of RSRM case segments and nozzle components by eliminating erosion due to multiple grit blasting during each use cycle and corrosion damage during marine recovery. Concurrent work for the Air Force show that other BOSS coatings give excellent bondline strength and durability for high-performance structures of aluminum and titanium.

  20. Evaluation of corrosive behavior of SAE 5155 by corrosion environment

    International Nuclear Information System (INIS)

    An, Jae Pil; Park, Keyung Dong

    2005-01-01

    In this study, the influence of shot peening and corrosive condition for corrosion property was investigated on immersed in 3.5% NaCl, 10% HNO 3 + 3% HF, 6% FeCl 3 . The immersion test was performed on two kinds of specimen. The immersion periods was performed 30days. Corrosion potential, weight loss were investigated from experimental results. From test results, the effect of shot peening on the corrosion was evaluated

  1. Cellulose acetate layer effect toward aluminium corrosion rate in hydrochloric acid media

    Science.gov (United States)

    Andarany, K. S.; Sagir, A.; Ahmad, A.; Deni, S. K.; Gunawan, W.

    2017-09-01

    Corrosion occurs due to the oxidation and reduction reactions between the material and its environment. The oxidation reaction defined as reactions that produce electrons and reduction is between two elements that bind the electrons. Corrosion cannot be inevitable in life both within the industry and household. Corrosion cannot eliminate but can be control. According to the voltaic table, Aluminum is a metal that easily corroded. This study attempts to characterize the type of corrosion by using a strong acid media (HCl). Experiment using a strong acid (HCl), at a low concentration that occurs is pitting corrosion, whereas at high concentrations that occurs is corrosion erosion. One of prevention method is by using a coating method. An efforts are made to slow the rate of corrosion is by coating the metal with “cellulose acetate” (CA). cellulose acetate consisted of cellulose powder dissolved in 99% acetic acid, and then applied to the aluminum metal. Soaking experiments using hydrochloric acid, cellulose acetate is able to slow down the corrosion rate of 47 479%.

  2. Estimation of elastic modulus of reinforcement corrosion products using inverse analysis of digital image correlation measurements for input in corrosion-induced cracking model

    DEFF Research Database (Denmark)

    Pease, Bradley Justin; Michel, Alexander; Thybo, Anna Emilie A.

    2012-01-01

    A combined experimental and numerical approach for estimating the elastic modulus of reinforcement corrosion products is presented. Deformations between steel and mortar were measured using digital image correlation during accelerated corrosion testing at 100 μA/cm2 (~1.16 mm/year). Measured...... deformations were compared to a numerical corrosion model that considers electrochemical, transport, and mechanical processes, including penetration of corrosion products into a ‘corrosion-accommodating region,’ provided by the mortar’s capillary porosity, directly surrounding the steel. Comparing model...

  3. Erosion and deposition in tokamaks

    International Nuclear Information System (INIS)

    Staudenmaier, G.

    1985-01-01

    The flow of metal impurities from the wall and limiter to the plasma, and back towards the wall, is investigated using surface collection probes and subsequent surface analysis in order to understand impuritiy generation and impurity transport. Impurity fluxes and their scrapeoff lengths have been investigated for several years in a large number of tokamaks. The results are summarized and discussed. Erosion exceeding deposition was first observed to occur at limiterlike structures closest to the plasma edge. Recently, a new probe has been developed to measure quantitatively the erosion in ASDEX. Subsequent quantitative surface analysis is performed in situ by electron induced x-ray analysis. Erosion caused either by ions (limiter) or charge exchange neutrals (wall) can be investigated separately. The erosion at the wall is about two orders of magnitude smaller than the erosion at limiterlike structures, which is of the order of one monolayer per discharge. Simultaneous measurements of deposition and erosion have been performed to elucidate net values of deposition and erosion

  4. New Developments in Mitigation of Microbiologically Influenced Corrosion

    National Research Council Canada - National Science Library

    Little, B; Lee, J; Ray, R

    2007-01-01

    .... These strategies include the following: 1) use of biofilms to inhibitor prevent corrosion and 2) manipulation (removal or addition) of an electron acceptor, including oxygen, sulfate and nitrate, to influence the microbial population.

  5. Gastric Mucosal Erosions - Radiologic evaluation -

    International Nuclear Information System (INIS)

    Kim, Seung Hyup

    1985-01-01

    70 cases of gastric mucosal erosions were diagnosed by double contrast upper gastrointestinal examinations and endoscopic findings. Analyzing the radiologic findings of these 70 cases of gastric mucosal erosions, the following results were obtained. 1. Among the total 70 cases, 65 cases were typical varioliform erosions showing central depressions and surrounding mucosal elevations. Remaining 5 cases were erosions of acute phase having multiple irregular depressions without surrounding elevations. 2. The gastric antrum was involved alone or in part in all cases. Duodenal bulb was involved with gastric antrum in 4 cases. 3. The majority of the cases had multiple erosions. There were only 2 cases of single erosion. 4. In 65 cases of varioliform erosions; 1) The diameter of the surrounding elevations varied from 3 to 20 mm with the majority (47 cases) between 6 and 10 mm. 2) In general, the surrounding elevations with sharp margin on double contrast films were also clearly demonstrated on compression films but those with faint margin were not. 3) The size of the central barium collections varied from pinpoint to 10 mm with the majority under 5 mm. The shape of the central barium collections in majority of the cases were round with a few cases of linear, triangular or star-shape. 5. In 5 cases of acute phase erosions; 1) All the 5 cases were females. 2) On double contrast radiography, all the cases showed multiple irregular depressed lesions without surrounding elevations. 3) 1 case had the history of hematemesis. 4) In 1 case, there was marked radiological improvement on follow-up study of 2 months interval. 6. In 23 cases, there were coexistent diseases with gastric mucosal erosions. These were 13 cases of duodenal bulb ulcers,7 cases of benign gastric ulcers and 3 others

  6. Investigation on the Recent Research Trend in the Corrosion Behaviour of Stainless Steel Weldment

    International Nuclear Information System (INIS)

    Kim, Hwan Tae; Kil, Sang Cheol; Hwang, Woon Suk

    2011-01-01

    The research trend in the corrosion behaviour of stainless steel weldment has been reviewed. The welding technology plays an important role in the fabrication of structure such as chemical plant, power plant, because welding can influence various factors in the performance of plant and equipment. This has led to an increasing attention towards the corrosion behaviour of weldment which has been one of the major issues for both welding and corrosion research engineers. The aim of this paper is to give a short survey of the recent technical trends of welding and corrosion including the electrochemical corrosion, stress corrosion cracking, and corrosion fatigue in connection with the welding materials, welding process, and welding fabrication. This study covers the corrosion behaviour of stainless steel weldment collected from the COMPENDEX DB analysis of published papers, research subject and research institutes

  7. Corrosion testing facilities in India

    International Nuclear Information System (INIS)

    Viswanathan, R.; Subramanian, Venu

    1981-01-01

    Major types of corrosion tests, establishment of specifications on corrosion testing and scope of their application in practice are briefly described. Important organizations in the world which publish specifications/standards are listed. Indian organizations which undertake corrosion testing and test facilities available at them are also listed. Finally in an appendix, a comprehensive list of specifications relevant to corrosion testing is given. It is arranged under the headings: environmental testing, humidity tests, salt spray/fog tests, immersion tests, specification corrosion phenomena, (tests) with respect to special corrosion media, (tests) with respect to specific corrosion prevention methods, and specific corrosion tests using electrical and electrochemical methods (principles). Each entry in the list furnishes information about: nature of the test, standard number, and its specific application. (M.G.B.)

  8. Corrosion inhibitors for concrete bridges.

    Science.gov (United States)

    2004-12-01

    Deicing salts and salt-water spray can cause serious corrosion problems for reinforced concrete bridge structures. : These problems can lead to costly and labor-intensive repair and even replacement of the structure. Surface applied : corrosion inhib...

  9. Modelling reinforcement corrosion in concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Geiker, Mette Rica; Stang, Henrik

    2012-01-01

    A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold is rea......, a numerical example is pre-sented, that illustrates the formation of corrosion cells as well as propagation of corrosion in a reinforced concrete structure.......A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold...

  10. Global evaluation of erosion rates in relation to tectonics

    Science.gov (United States)

    Hecht, Hagar; Oguchi, Takashi

    2017-12-01

    Understanding the mechanisms and controlling factors of erosion rates is essential in order to sufficiently comprehend bigger processes such as landscape evolution. For decades, scientists have been researching erosion rates where one of the main objectives was to find the controlling factors. A variety of parameters have been suggested ranging from climate-related, basin morphometry and the tectonic setting of an area. This study focuses on the latter. We use previously published erosion rate data obtained mainly using 10Be and sediment yield and sediment yield data published by the United States Geological Survey. We correlate these data to tectonic-related factors, i.e., distance to tectonic plate boundary, peak ground acceleration ( PGA), and fault distribution. We also examine the relationship between erosion rate and mean basin slope and find significant correlations of erosion rates with distance to tectonic plate boundary, PGA, and slope. The data are binned into high, medium, and low values of each of these parameters and grouped in all combinations. We find that groups with a combination of high PGA (> 0.2.86 g) and long distance (> 1118.69 km) or low PGA (erosion rates include long distance and/or low PGA, and groups with high erosion rates include neither of these. These observations indicate that tectonics plays a major role in determining erosion rates, which is partly ascribable to steeper slopes produced by active crustal movements. However, our results show no apparent correlation of slope with erosion rates, pointing to problems with using mean basin-wide slope as a slope indicator because it does not represent the complex slope distribution within a basin.

  11. Propagation of steel corrosion in concrete: Experimental and numerical investigations

    DEFF Research Database (Denmark)

    Michel, Alexander; Otieno, M.; Stang, Henrik

    2016-01-01

    This paper focuses on experimental and numerical investigations of the propagation phase of reinforcement corrosion to determine anodic and cathodic Tafel constants and exchange current densities, from corrosion current density and corrosion potential measurements. The experimental program includ...... through numerical simulations of the experimental data. Anodic and cathodic exchange current densities ranged from 1.0E-12 to 1.0E-09 A/mm2 and 1.0E-12 to 1.1E-09 A/mm2, respectively.......This paper focuses on experimental and numerical investigations of the propagation phase of reinforcement corrosion to determine anodic and cathodic Tafel constants and exchange current densities, from corrosion current density and corrosion potential measurements. The experimental program included....... The numerical model was, furthermore, used to identify electrochemical parameters, which are independent of concrete cover thickness and crack width and at the same time allow for determination of the corrosion current density and corrosion potential of concrete structures within an acceptable error.Very good...

  12. Atmospheric corrosion of mild steel

    OpenAIRE

    Morcillo, M.; de la Fuente, D.; Díaz, I.; Cano, H.

    2011-01-01

    The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a) the morphology of steel c...

  13. Atmospheric corrosion of mild steel

    OpenAIRE

    Morcillo, Manuel; Fuente, Daniel de la; Díaz, Iván; Cano, H.

    2011-01-01

    The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a) the morpholog...

  14. Silicon carbide corrosion in HTGR fuel particles

    International Nuclear Information System (INIS)

    Gruebmeier, H.; Naoumidis, A.; Thiele, B.A.

    1977-01-01

    The silicon carbide layer in TRISO-coated HTR fuel particles occasionally is attacked during irradiation by fission products generated within the kernel material. Investigations to define the cause of the SiC corrosion are described, which included ceramographic, microradiographic and microanalytical studies on irradiated and unirradiated coated particles of various kernel compositions. The results of these studies showed that the presence of chlorine within the particle, in combination with certain metallic fission products or uranium, can lead to corrosion of the SiC layer. These results provided the basis for establishing a model, which relates the transport of fission products as volatile metal chlorides and their chemical reaction with the SiC corrosion. In addition this model is consistent with the fact that under the influence of a thermal gradient corrosive attack of the SiC occurs on the cooler side of the particle. The correlation between the occurrence of SiC corrosion during irradiation and heavy-metal transport observed in thermal gradient annealing studies of unirradiated particles of the same barch constitutes the basis for a new method for quality control. (orig.) [de

  15. Corrosion of Magnesium in Multimaterial System

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Vineet V.; Agnew, Sean

    2017-08-16

    The TMS Magnesium Committee has been actively involved in presenting cutting-edge research and development and the latest trends related to magnesium and its alloys to industry and academia. Topics including magnesium alloy development, applications, mechanism of deformation and corrosion, thermomechanical processing, modelling, etc. have been captured year after year through the Magnesium Technology symposium and conference proceedings at TMS and through special topics in JOM. Every year, based on the unanimous endorsement from the industry and academia, a topic is selected to address the latest developments within this subject in JOM. In continuation with last year’s coverage of Advances and Achievements in In-Situ Analysis of Corrosions and Structure–Property Relationship in Mg Alloys,[1] this year’s topic focuses on the Corrosion of Magnesium in Multimaterial Systems. Magnesium, the lightest of all the structural materials, has garnered much interest in the transportation, electronics packaging, defense equipments and industries alike and are more commonly being incorporated in multimaterial design concepts.[2-4] However, the application of the same is limited due to its highly corrosive nature, and understanding and mitigating the corrosion of magnesium has been a major research challenge.

  16. Plastics for corrosion inhibition

    CERN Document Server

    Goldade, Victor A; Makarevich, Anna V; Kestelman, Vladimir N

    2005-01-01

    The development of polymer composites containing inhibitors of metal corrosion is an important endeavour in modern materials science and technology. Corrosion inhibitors can be located in a polymer matrix in the solid, liquid or gaseous phase. This book details the thermodynamic principles for selecting these components, their compatibility and their effectiveness. The various mechanisms of metal protection – barrier, inhibiting and electromechanical – are considered, as are the conflicting requirements placed on the structure of the combined material. Two main classes of inhibited materials (structural and films/coatings) are described in detail. Examples are given of structural plastics used in friction units subjected to mechano-chemical wear and of polymer films/coatings for protecting metal objects against corrosion.

  17. The corrosion of depleted uranium in terrestrial and marine environments.

    Science.gov (United States)

    Toque, C; Milodowski, A E; Baker, A C

    2014-02-01

    Depleted Uranium alloyed with titanium is used in armour penetrating munitions that have been fired in a number of conflict zones and testing ranges including the UK ranges at Kirkcudbright and Eskmeals. The study presented here evaluates the corrosion of DU alloy cylinders in soil on these two UK ranges and in the adjacent marine environment of the Solway Firth. The estimated mean initial corrosion rates and times for complete corrosion range from 0.13 to 1.9 g cm(-2) y(-1) and 2.5-48 years respectively depending on the particular physical and geochemical environment. The marine environment at the experimental site was very turbulent. This may have caused the scouring of corrosion products and given rise to a different geochemical environment from that which could be easily duplicated in laboratory experiments. The rate of mass loss was found to vary through time in one soil environment and this is hypothesised to be due to pitting increasing the surface area, followed by a build up of corrosion products inhibiting further corrosion. This indicates that early time measurements of mass loss or corrosion rate may be poor indicators of late time corrosion behaviour, potentially giving rise to incorrect estimates of time to complete corrosion. The DU alloy placed in apparently the same geochemical environment, for the same period of time, can experience very different amounts of corrosion and mass loss, indicating that even small variations in the corrosion environment can have a significant effect. These effects are more significant than other experimental errors and variations in initial surface area. Copyright © 2013. Published by Elsevier Ltd.

  18. Structural Effects of Reinforced Concrete Beam Due to Corrosion

    Science.gov (United States)

    Noh, Hamidun Mohd; Idris, Nur'ain; Noor, Nurazuwa Md; Sarpin, Norliana; Zainal, Rozlin; Kasim, Narimah

    2018-03-01

    Corrosion of steel in reinforced concrete is one of the main issues among construction stakeholders. The main consequences of steel corrosion include loss of cross section of steel area, generation of expansive pressure which caused cracking of concrete, spalling and delaminating of the concrete cover. Thus, it reduces the bond strength between the steel reinforcing bar and concrete, and deteriorating the strength of the structure. The objective of this study is to investigate the structural effects of corrosion damage on the performance of reinforced concrete beam. A series of corroded reinforced concrete beam with a corrosion rate of 0%, 20% and 40% of rebar corrosion is used in parametric study to assess the influence of different level of corrosion rate to the structural performance. As a result, the used of interface element in the finite element modelling predicted the worst case of corrosion analysis since cracks is induced and generate at this surface. On the other hand, a positive linear relationship was sketched between the increase of expansive pressure and the corrosion rate. Meanwhile, the gradient of the graph is decreased with the increase of steel bar diameter. Furthermore, the analysis shows that there is a significant effect on the load bearing capacity of the structure where the higher corrosion rate generates a higher stress concentration at the mid span of the beam. This study could predict the residual strength of reinforced concrete beam under the corrosion using the finite element analysis. The experimental validation is needed on the next stage to investigate the quantitative relation between the corrosion rate and its influence on the mechanical properties.

  19. Structural Effects of Reinforced Concrete Beam Due to Corrosion

    Directory of Open Access Journals (Sweden)

    Mohd Noh Hamidun

    2018-01-01

    Full Text Available Corrosion of steel in reinforced concrete is one of the main issues among construction stakeholders. The main consequences of steel corrosion include loss of cross section of steel area, generation of expansive pressure which caused cracking of concrete, spalling and delaminating of the concrete cover. Thus, it reduces the bond strength between the steel reinforcing bar and concrete, and deteriorating the strength of the structure. The objective of this study is to investigate the structural effects of corrosion damage on the performance of reinforced concrete beam. A series of corroded reinforced concrete beam with a corrosion rate of 0%, 20% and 40% of rebar corrosion is used in parametric study to assess the influence of different level of corrosion rate to the structural performance. As a result, the used of interface element in the finite element modelling predicted the worst case of corrosion analysis since cracks is induced and generate at this surface. On the other hand, a positive linear relationship was sketched between the increase of expansive pressure and the corrosion rate. Meanwhile, the gradient of the graph is decreased with the increase of steel bar diameter. Furthermore, the analysis shows that there is a significant effect on the load bearing capacity of the structure where the higher corrosion rate generates a higher stress concentration at the mid span of the beam. This study could predict the residual strength of reinforced concrete beam under the corrosion using the finite element analysis. The experimental validation is needed on the next stage to investigate the quantitative relation between the corrosion rate and its influence on the mechanical properties.

  20. [Application of spark erosion technology in manufacture of implant prosthesis].

    Science.gov (United States)

    Cui, H Y; DI, P; Li, J H; Lin, Y; Liu, R R

    2015-04-18

    To evaluate the influence of the implant-supported porcelain bridges made from non-precious metals using spark erosion techniques, and to discuss the feasibility and details of making the implant restoration by spark erosion technique. The study included 12 patients (9 males and 3 females) with 92 units implant-supported non-precious porcelain bridge from Sep. 2011 to Feb. 2013. All the patients received implant treatment in Department of Oral Implantology, Peking University School and Hospital of Stomatology. The total of 52 implants, were from Nobel Biocare implant system, Camlog implant system and Ankylos implant system. The implant analogs were connected in sequence with a copper wire to guarantee conductivity. The implant electrodes represented one electrode and the superstructure the other. During spark-erosion machining, the cast holding the implant electrodes and the prosthetic framework were moved toward one another, causing an electrical erosion of the protruding elements. After the spark-erosion machining, the minimum gap between the framework and abutment was 0.21 mm, which was two units bridge. The maximum was 2.59 mm, which was 11 units bridge with 6 implants. The average gap was 0.68 mm. After the spark-erosion machining, the bridge fitted well with the passive position stability. The method of making implant-supported non-precious porcelain bridge reduces costs on patients. Spark erosion has the potential to provide implant framework with an excellent fit. The patients are satisfied with the clinical results.

  1. Review of hot corrosion of thermal barrier coatings of gas turbine

    Directory of Open Access Journals (Sweden)

    LIU Yongbao

    2017-03-01

    Full Text Available The review was done in order to make clear the problem of the hot corrosion of the Thermal Barrier Coatings(TBCsduring gas turbine serving. This paper summarizes the factors resulting from the hot corrosion of TBCs during turbine service and classifies methods for enhancing the corrosive resistance of TBCs. A prospective methodology for improving corrosion resistance is also formulated. The main types of corrosion coating include phase reaction, oxidizing of the bond coating, salt-fog corrosion, CMAS corrosion and fuel impurity corrosion. So far, methods for improving the corrosion resistance of TBCs include developing new coating materials, anticorrosive treatment on the surface of TBCs, modifying the stacking configuration and improving the cleansing functions of the gas turbines. In the future, developing new materials with excellent performance will still be the main direction for boosting the improvement of the hot corrosion resistance of TBCs. Simultaneously, improving the tacking configuration and nanotechnology of TBC coatings are potential approaches for improving corrosion resistance. With the development of a Ceramic Matrix Composite (CMC, the focus of the hot corrosion of TBCs may turn to that of Environmental Barrier Coatings (EBCs.

  2. 219-S CORROSION STUDY

    International Nuclear Information System (INIS)

    DIVINE, J.R.; PARSONS, G.L.

    2008-01-01

    A minor leak was detected in a drain line for Hood 2B located in the 222-S Laboratory. The line transfers radioactive waste, spent analytical standards, and chemicals used in various analytical procedures. Details are in the report provided by David Comstock, 2B NDE June 2008, work package LAB-WO-07-2012. Including the noted leak, the 222-S Laboratory has experienced two drain line leaks in approximately the last two years of operation. As a consequence, CH2M HILL Hanford Group, Inc. (CH2M HILL) requested the support of ChemMet, Ltd., PC (ChemMet) at the Hanford Site 222-S Laboratory. The corrosion expertise from ChemMet was required prior to preparation of a compatibility assessment for the 222-S Laboratory waste transfer system to assure the expected life of the piping system is extended as much as practicable. The system includes piping within the 222-S Laboratory and the 219-S Waste Storage and Transfer Facility and Operations Process. The ChemMet support was required for an assessment by 222-S staff to analyze what improvements to operational activities may be implemented to extend the tank/piping system life. This assessment will include a summary of the various material types, age, and locations throughout the facility. The assessment will also include a discussion of materials that are safe for drain line disposal on a regular basis, materials that are safe for disposal on a case-by-case basis including specific additional requirements such as flushing, neutralization to a specific pH, and materials prohibited from disposal. The assessment shall include adequate information for 222-S Laboratory personnel to make informed decisions in the future disposal of specific material types by discussing types of compatibility of system materials and potential wastes. The assessment is expected to contain some listing of acceptable waste materials but is not anticipated to be a complete or comprehensive list. Finally the assessment will encompass a brief discussion of

  3. Erosive tooth wear in children

    NARCIS (Netherlands)

    Carvalho, T.S.; Lussi, A.; Jaeggi, T.; Gambon, D.L.; Lussi, A.; Ganss, C.

    2014-01-01

    Erosive tooth wear in children is a common condition. Besides the anatomical differences between deciduous and permanent teeth, additional histological differences may influence their susceptibility to dissolution. Considering laboratory studies alone, it is not clear whether deciduous teeth are

  4. Compost for steep slope erosion.

    Science.gov (United States)

    2008-06-01

    This study was initiated to develop guidelines for maintenance erosion control measures for steep slopes. The study focused on evaluating and monitoring KY-31 fescue germination rates using two media treatments 1) 100 percent by weight compost and 2)...

  5. Erosion-resistant composite material

    Science.gov (United States)

    Finch, C.B.; Tennery, V.J.; Curlee, R.M.

    A highly erosion-resistant composite material is formed of chemical vapor-deposited titanium diboride on a sintered titanium diboride-nickel substrate. This material may be suitable for use in cutting tools, coal liquefaction systems, etc.

  6. Polymer Composites Corrosive Degradation: A Computational Simulation

    Science.gov (United States)

    Chamis, Christos C.; Minnetyan, Levon

    2007-01-01

    A computational simulation of polymer composites corrosive durability is presented. The corrosive environment is assumed to manage the polymer composite degradation on a ply-by-ply basis. The degradation is correlated with a measured pH factor and is represented by voids, temperature and moisture which vary parabolically for voids and linearly for temperature and moisture through the laminate thickness. The simulation is performed by a computational composite mechanics computer code which includes micro, macro, combined stress failure and laminate theories. This accounts for starting the simulation from constitutive material properties and up to the laminate scale which exposes the laminate to the corrosive environment. Results obtained for one laminate indicate that the ply-by-ply degradation degrades the laminate to the last one or the last several plies. Results also demonstrate that the simulation is applicable to other polymer composite systems as well.

  7. High Temperature Corrosion on Biodust Firing

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi

    conditions and is accelerated once the material encounters a higher temperature. For the investigated austenitic stainless steels, FeCrAl alloys and Ni-based superalloy, the formation of a protective oxide layer that suppressed corrosion attack was not observed. However, it was established that among...... the alloying elements present in these alloys, Ni exhibits a relatively greater resistance to corrosion attack. Surface modification approaches with the aim to form resistant oxides or coatings on superheater surfaces were evaluated. This included preoxidation to obtain Al2O3 and Ti-Cr-rich oxides, as well...... as formation of SiOx coating, Ni electroplating and NiAl coatings on commercial alloys. For most of the modified surfaces, in particular α-Al2O3 obtained by preoxidation, poor mechanical integrity of the oxide layer nullifies its otherwise excellent chemical integrity towards corrosion attack. Nonetheless...

  8. Strain rate effects in stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Parkins, R.N. (Newcastle upon Tyne Univ. (UK). Dept. of Metallurgy and Engineering Materials)

    1990-03-01

    Slow strain rate testing (SSRT) was initially developed as a rapid, ad hoc laboratory method for assessing the propensity for metals an environments to promote stress corrosion cracking. It is now clear, however, that there are good theoretical reasons why strain rate, as opposed to stress per se, will often be the controlling parameter in determining whether or not cracks are nucleated and, if so, are propagated. The synergistic effects of the time dependence of corrosion-related reactions and microplastic strain provide the basis for mechanistic understanding of stress corrosion cracking in high-pressure pipelines and other structures. However, while this may be readily comprehended in the context of laboratory slow strain tests, its extension to service situations may be less apparent. Laboratory work involving realistic stressing conditions, including low-frequency cyclic loading, shows that strain or creep rates give good correlation with thresholds for cracking and with crack growth kinetics.

  9. Structural Composites Corrosive Management by Computational Simulation

    Science.gov (United States)

    Chamis, Christos C.; Minnetyan, Levon

    2006-01-01

    A simulation of corrosive management on polymer composites durability is presented. The corrosive environment is assumed to manage the polymer composite degradation on a ply-by-ply basis. The degradation is correlated with a measured Ph factor and is represented by voids, temperature, and moisture which vary parabolically for voids and linearly for temperature and moisture through the laminate thickness. The simulation is performed by a computational composite mechanics computer code which includes micro, macro, combined stress failure, and laminate theories. This accounts for starting the simulation from constitutive material properties and up to the laminate scale which exposes the laminate to the corrosive environment. Results obtained for one laminate indicate that the ply-by-ply managed degradation degrades the laminate to the last one or the last several plies. Results also demonstrate that the simulation is applicable to other polymer composite systems as well.

  10. Comment on "Rainfall erosivity in Europe" by Panagos et al. (Sci. Total Environ., 511, 801-814, 2015).

    Science.gov (United States)

    Auerswald, Karl; Fiener, Peter; Gomez, José A; Govers, Gerard; Quinton, John N; Strauss, Peter

    2015-11-01

    Recently a rainfall erosivity map has been published. We show that the values of this map contain considerable bias because (i) the temporal resolution of the rain data was insufficient, which likely underestimates rain erosivity by about 20%, (ii) no attempt had been included to account for the different time periods that were used for different countries, which can modify rain erosivity by more than 50%, (iii) and likely precipitation data had been used instead of rain data and thus rain erosivity is overestimated in areas with significant snowfall. Furthermore, the seasonal distribution of rain erosivity is not provided, which does not allow using the erosivity map for erosion prediction in many cases. Although a rain erosivity map for Europe would be highly desirable, we recommend using the national erosivity maps until these problems have been solved. Such maps are available for many European countries. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. General Corrosion and Localized Corrosion of the Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua; K. Mon

    2003-06-24

    The recommended waste package (WP) design is described in BSC (2001a). The design includes a double-wall WP underneath a protective drip shield (DS) (BSC 2003a). The purpose of the process-level models developed in this report is to model dry oxidation (DOX), general corrosion (GC) and localized corrosion (LC) of the DS plate material, which is made of Ti Grade 7. The DS design also includes structural supports fabricated from Ti Grade 24. Degradation of Ti Grade 24 is not considered in this report. The DS provides protection for the waste package outer barrier (WPOB) both as a barrier to seepage water contact and a physical barrier to potential rockfall. This Model Report (MR) serves as a feed to the Integrated Waste Package Degradation Model (IWPD) analyses, and was developed in accordance with the Technical Work Plan (TWP) (BSC 2002a). The models contained in this report serve as a basis to determine whether or not the performance requirements for the DS can be met.

  12. General Corrosion and Localized Corrosion of the Drip Shield

    International Nuclear Information System (INIS)

    Hua, F.; Mon, K.

    2003-01-01

    The recommended waste package (WP) design is described in BSC (2001a). The design includes a double-wall WP underneath a protective drip shield (DS) (BSC 2003a). The purpose of the process-level models developed in this report is to model dry oxidation (DOX), general corrosion (GC) and localized corrosion (LC) of the DS plate material, which is made of Ti Grade 7. The DS design also includes structural supports fabricated from Ti Grade 24. Degradation of Ti Grade 24 is not considered in this report. The DS provides protection for the waste package outer barrier (WPOB) both as a barrier to seepage water contact and a physical barrier to potential rockfall. This Model Report (MR) serves as a feed to the Integrated Waste Package Degradation Model (IWPD) analyses, and was developed in accordance with the Technical Work Plan (TWP) (BSC 2002a). The models contained in this report serve as a basis to determine whether or not the performance requirements for the DS can be met

  13. High Temperature Corrosion Problem of Boiler Components in presence of Sulfur and Alkali based Fuels

    Science.gov (United States)

    Ghosh, Debashis; Mitra, Swapan Kumar

    2011-04-01

    Material degradation and ageing is of particular concern for fossil fuel fired power plant components. New techniques/approaches have been explored in recent years for Residual Life assessment of aged components and material degradation due to different damage mechanism like creep, fatigue, corrosion and erosion etc. Apart from the creep, the high temperature corrosion problem in a fossil fuel fired boiler is a matter of great concern if the fuel contains sulfur, chlorine sodium, potassium and vanadium etc. This paper discusses the material degradation due to high temperature corrosion in different critical components of boiler like water wall, superheater and reheater tubes and also remedial measures to avoid the premature failure. This paper also high lights the Residual Life Assessment (RLA) methodology of the components based on high temperature fireside corrosion. of different critical components of boiler.

  14. Wind erosion of soils burned by wildfire

    Science.gov (United States)

    N. S. Wagenbrenner; M. J. Germino; B. K. Lamb; R. B. Foltz; P. R. Robichaud

    2011-01-01

    Wind erosion and aeolian transport processes are largely unstudied in the post-wildfire environment, but recent studies have shown that wind erosion can play a major role in burned landscapes. A wind erosion monitoring system was installed immediately following a wildfire in southeastern Idaho, USA to measure wind erosion from the burned area (Figure 1). This paper...

  15. Relationship between corrosion and the biological sulfur cycle: A review

    Energy Technology Data Exchange (ETDEWEB)

    Little, B.J.; Ray, R.I.; Pope, R.K.

    2000-04-01

    Sulfur and sulfur compounds can produce pitting, crevice corrosion, dealloying, stress corrosion cracking, and stress-oriented hydrogen-induced cracking of susceptible metals and alloys. Even though the metabolic by-products of the biological sulfur cycle are extremely corrosive, there are no correlations between numbers and types of sulfur-related organisms and the probability or rate of corrosion, Determination of specific mechanisms for corrosion caused by microbiologically mediated oxidation and reduction of sulfur and sulfur compounds is complicated by the variety of potential metabolic-energy sources and by-products; the coexistence of reduced and oxidized sulfur species; competing reactions with inorganic and organic compounds; and the versatility and adaptability of microorganisms in biofilms. The microbial ecology of sulfur-rich environments is poorly understood because of the association of aerobes and anaerobes and the mutualism or succession of heterotrophs to autotrophs. The physical scale over which the sulfur cycle influences corrosion varies with the environment. The complete sulfur cycle of oxidation and reduction reactions can take place in macroenvironments, including sewers and polluted harbors, or within the microenvironment of biofilms. In this review, reactions of sulfur and sulfur compounds resulting in corrosion were discussed in the context of environmental processes important to corrosion.

  16. Research process of nondestructive testing pitting corrosion in metal material

    Directory of Open Access Journals (Sweden)

    Bo ZHANG

    2017-12-01

    Full Text Available Pitting corrosion directly affects the usability and service life of metal material, so the effective nondestructive testing and evaluation on pitting corrosion is of great significance for fatigue life prediction because of data supporting. The features of pitting corrosion are elaborated, and the relation between the pitting corrosion parameters and fatigue performance is pointed out. Through introducing the fundamental principles of pitting corrosion including mainly magnetic flux leakage inspection, pulsed eddy current and guided waves, the research status of nondestructive testing technology for pitting corrosion is summarized, and the key steps of nondestructive testing technologies are compared and analyzed from the theoretical model, signal processing to industrial applications. Based on the analysis of the signal processing specificity of different nondestructive testing technologies in detecting pitting corrosion, the visualization combined with image processing and signal analysis are indicated as the critical problems of accurate extraction of pitting defect information and quantitative characterization for pitting corrosion. The study on non-contact nondestructive testing technologies is important for improving the detection precision and its application in industries.

  17. Minimize corrosion degradation of steam generator tube materials

    International Nuclear Information System (INIS)

    Lu, Y.

    2006-01-01

    As part of a coordinated program, AECL is developing a set of tools to aid with the prediction and management of steam generator performance. Although stress corrosion cracking (of Alloy 800) has not been detected in any operating steam generator, for life management it is necessary to develop mechanistic models to predict the conditions under which stress corrosion cracking is plausible. Experimental data suggest that all steam generator tube materials are susceptible to corrosion degradation under some specific off-specification conditions. The tolerance to the chemistry upset for each steam generator tube alloy is different. Electrochemical corrosion behaviors of major steam generator tube alloys were studied under the plausible aggressive crevice chemistry conditions. The potential hazardous conditions leading to steam generator tube degradation and the conditions, which can minimize steam generator tube degradation have been determined. Recommended electrochemical corrosion potential/pH zones were defined for all major steam generator tube materials, including Alloys 600, 800, 690 and 400, under CANDU steam generator operating and startup conditions. Stress corrosion cracking tests and accelerated corrosion tests were carried out to verify and revise the recommended electrochemical corrosion potential/pH zones. Based on this information, utilities can prevent steam generator material degradation surprises by appropriate steam generator water chemistry management and increase the reliability of nuclear power generating stations. (author)

  18. What can we learn from national-scale geodata describing soil erosion?

    Science.gov (United States)

    Benaud, Pia; Anderson, Karen; Carvalho, Jason; Evans, Martin; Glendell, Miriam; James, Mike; Lark, Murray; Quine, Timothy; Quinton, John; Rawlins, Barry; Rickson, Jane; Truckell, Ian; Brazier, Richard

    2017-04-01

    The United Kingdom has a rich dataset of soil erosion observations, which have been collected using a wide range of methodologies, across various spatial and temporal scales. Yet, while observations of soil erosion have been carried out along-side agricultural development and intensification, understanding whether or not the UK has a soil erosion problem remains a question to be answered. Furthermore, although good reviews of existing soil erosion rates exist, there is no single resource that brings all of this work together. Therefore, the primary aim of this research was to build a picture of why attempts to quantify erosion rates across the UK empirically have fallen short, through: (1) Collating all available, UK-based and empirically-derived soil erosion datasets into a spatially explicit and open-access database, (2) Developing an understanding of observed magnitudes of erosion, in the UK, (3) Evaluating impact of non-environmental controls on erosion observations i.e. study methodologies, and (4) Exploring trends between environmental controls and erosion rates. To-date, the database holds over 1500 records, which include results from both experimental and natural conditions, across arable, grassland and upland environments. Of the studies contained in the database, erosion has been observed ca. 40% of instances, ranging from soil loss via visible erosion features, such as rills or gullies, through volumetric assessments. Furthermore, there has been an inherent bias in the UK towards quantifying soil erosion in locations with either a known history or high probability of erosion occurrence. As a consequence, we conclude that such databases, may not be used to make a statistically unbiased assessment of national-scale erosion rates, however, they can highlight maximum likely rates under a wide range of soil, topography and land use conditions. Finally, this work suggests there is a strong argument for a replicable and statistically robust national soil

  19. Analysis of C-MOD molybdenum divertor erosion and code/data comparison

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, J.N., E-mail: brooksjn@purdue.edu [Purdue University, West Lafayette, IN (United States); Allain, J.P. [Purdue University, West Lafayette, IN (United States); Whyte, D.G.; Ochoukov, R.; Lipschultz, B. [Massachusetts Institute of Technology, Cambridge, MA (United States)

    2011-08-01

    We analyze an important 15 year old Alcator C-MOD study of campaign-integrated molybdenum divertor erosion in which the measured net erosion was significantly higher ({approx}X3) than originally predicted by a simple model . We perform full process sputtering erosion/redeposition computational analysis including the effect of a possible RF induced sheath. The simulations show that most sputtered Mo atoms are ionized close to the surface and strongly redeposited, via Lorentz force motion and collisional friction with the high density incoming plasma. The predicted gross erosion profile is a reasonable match to MoI influx data, however, the critically important net erosion comparison with post-exposure Mo tile analysis is poor, with {approx}X10 higher peak erosion measured than computed. An RF sheath increases predicted erosion by {approx}45%, thus being significant but not fundamental. We plan future analysis.

  20. Erosion characteristics and horizontal variability for small erosion depths in the Sacramento-San Joaquin River Delta, California, USA

    Science.gov (United States)

    Schoellhamer, David H.; Manning, Andrew J.; Work, Paul

    2017-01-01

    Erodibility of cohesive sediment in the Sacramento-San Joaquin River Delta (Delta) was investigated with an erosion microcosm. Erosion depths in the Delta and in the microcosm were estimated to be about one floc diameter over a range of shear stresses and times comparable to half of a typical tidal cycle. Using the conventional assumption of horizontally homogeneous bed sediment, data from 27 of 34 microcosm experiments indicate that the erosion rate coefficient increased as eroded mass increased, contrary to theory. We believe that small erosion depths, erosion rate coefficient deviation from theory, and visual observation of horizontally varying biota and texture at the sediment surface indicate that erosion cannot solely be a function of depth but must also vary horizontally. We test this hypothesis by developing a simple numerical model that includes horizontal heterogeneity, use it to develop an artificial time series of suspended-sediment concentration (SSC) in an erosion microcosm, then analyze that time series assuming horizontal homogeneity. A shear vane was used to estimate that the horizontal standard deviation of critical shear stress was about 30% of the mean value at a site in the Delta. The numerical model of the erosion microcosm included a normal distribution of initial critical shear stress, a linear increase in critical shear stress with eroded mass, an exponential decrease of erosion rate coefficient with eroded mass, and a stepped increase in applied shear stress. The maximum SSC for each step increased gradually, thus confounding identification of a single well-defined critical shear stress as encountered with the empirical data. Analysis of the artificial SSC time series with the assumption of a homogeneous bed reproduced the original profile of critical shear stress, but the erosion rate coefficient increased with eroded mass, similar to the empirical data. Thus, the numerical experiment confirms the small-depth erosion hypothesis. A linear

  1. Corrosion of bio implants

    Indian Academy of Sciences (India)

    Chemical stability, mechanical behaviour and biocompatibility in body fluids and tissues are the basic requirements for successful application of implant materials in bone fractures and replacements. Corrosion is one of the major processes affecting the life and service of orthopaedic devices made of metals and alloys used ...

  2. Corrosion resistant steel

    International Nuclear Information System (INIS)

    Zubchenko, A.S.; Borisov, V.P.; Latyshev, V.B.

    1980-01-01

    Corrosion resistant steel for production of sheets and tubes containing C, Mn, Cr, Si, Fe is suggested. It is alloyed with vanadium and cerium for improving tensile properties and ductility. The steel can be melted by a conventional method in electric-arc or induction furnaces. The mentioned steel is intended to be used as a substitute for nickel-bearing austenitic steels

  3. Corrosion in seawater systems

    International Nuclear Information System (INIS)

    Henrikson, S.

    1988-01-01

    Highly alloyed stainless steels have been exposed to natural chlorinated and chlorine-free seawater at 35 deg. C. Simulated tube-tubesheet joints, weld joints and galvanic couples with titanium, 90/10 CuNi and NiAl bronze were tested and evaluated for corrosion. The corrosion rates of various anode materials - zinc, aluminium and soft iron - were also determined. Finally the risk of hydrogen embrittlement of tubes of ferritic stainless steels and titanium as a consequence of cathodic protection was studied. An attempt was also made to explain the cracking mechanism of the ferritic steels by means of transmission electron microscopy. One important conclusion of the project is that chlorinated seawater is considerably more corrosive to stainless steels than chlorine-free water, whereas chlorination reduces the rate of galvanic corrosion of copper materials coupled to stainless steels. Hydrogen embrittlement of ferritic stainless steels and titanium as a consequence of cathodic protection of carbon steel or cast iron in the same structure can be avoided by strict potentiostatic control of the applied potential. (author)

  4. [Gastric band erosion: Alternative management].

    Science.gov (United States)

    Echaverry-Navarrete, Denis José; Maldonado-Vázquez, Angélica; Cortes-Romano, Pablo; Cabrera-Jardines, Ricardo; Mondragón-Pinzón, Erwin Eduardo; Castillo-González, Federico Armando

    2015-01-01

    Obesity is a public health problem, for which the prevalence has increased worldwide at an alarming rate, affecting 1.7 billion people in the world. To describe the technique employed in incomplete penetration of gastric band where endoscopic management and/or primary closure is not feasible. Laparoscopic removal of gastric band was performed in five patients with incomplete penetrance using Foley catheterization in the perforation site that could lead to the development of a gastro-cutaneous fistula. The cases presented include a leak that required surgical lavage with satisfactory outcome, and one patient developed stenosis 3 years after surgical management, which was resolved endoscopically. In all cases, the penetration site closed spontaneously. Gastric band erosion has been reported in 3.4% of cases. The reason for inserting a catheter is to create a controlled gastro-cutaneous fistula, allowing spontaneous closure. Various techniques have been described: the totally endoscopic, hybrid techniques (endoscopic/laparoscopic) and completely laparoscopic. A technique is described here that is useful and successful in cases where the above-described treatments are not viable. Copyright © 2015. Published by Masson Doyma México S.A.

  5. Smart Coatings for Corrosion Protection

    Science.gov (United States)

    Calle, Luz Marina; Li, Wendy; Buhrow, Jerry W.; Johnsey, Marissa N.

    2016-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it.

  6. Soil erosion and its control in Chile - An overview

    International Nuclear Information System (INIS)

    Ellies, A.

    2000-01-01

    Accelerate erosion in Chile is a consequence from land use that degrade soil such as compaction, loss of organic matter and soil structure. The erosion is favored by the very hilly landscape of the country that increases erosivity index and the high erodibility given by an elevated annual rate of rainfall with irregular distribution. Several experiences have demonstrated that adequate crop management and crop rotations can minimize erosion. The most effective control is achieved conserving and improving soil structure with management systems that include regular use of soil-improving crops, return of crop residues and tillage practices, thus avoiding unnecessary breakdown soil or compacted soil structure. Conservation tillage increased organic matter levels improving stabile soil structure, aeration and infiltration. (author) [es

  7. Hanford double shell waste tank corrosion studies - final report FY2014

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fuentes, R. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hicks, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2014-12-19

    SRNL tasks for FY14 included studies to evaluate the susceptibility of carbon steel to vapor space corrosion (VSC), liquid-air interface (LAI) corrosion, and pitting corrosion. Additionally, SRNL evaluated the susceptibility of carbon steel to pitting corrosion under buffered waste conditions, with the objective of determining the adequate amount of inhibitor (e.g., nitrite) necessary to mitigate pitting corrosion. Other CPP experiments were performed in historical waste simulants and the results were compared to previously gathered results. The results of these activities were utilized to assess the robustness of the standardized CPP protocol

  8. Corrosion detector apparatus for universal assessment of pollution in data centers

    Science.gov (United States)

    Hamann, Hendrik F.; Klein, Levente I.

    2015-08-18

    A compact corrosion measurement apparatus and system includes an air fan, a corrosion sensor, a temperature sensor, a humidity sensor, a heater element, and an air flow sensor all under control to monitor and maintain constant air parameters in an environment and minimize environmental fluctuations around the corrosion sensor to overcome the variation commonly encountered in corrosion rate measurement. The corrosion measurement apparatus includes a structure providing an enclosure within which are located the sensors. Constant air flow and temperature is maintained within the enclosure where the corrosion sensor is located by integrating a variable speed air fan and a heater with the corresponding feedback loop control. Temperature and air flow control loops ensure that corrosivity is measured under similar conditions in different facilities offering a general reference point that allow a one to one comparison between facilities with similar or different pollution levels.

  9. Effective Utilization for Data of Natural Environment Corrosion of Materials

    Directory of Open Access Journals (Sweden)

    Haitao Wang

    2015-05-01

    Full Text Available An analysis architecture is built to make full use of natural environment corrosion of materials data. All environmental factors, such as average temperature, average relative humidity, rainfall hours, sunshine duration, chloride ion settlement, etc., in nine atmospheric test stations, including Beijing, Wuhan, Jiangjin, and Wanning, and seawater temperature, salinity, dissolved oxygen, pH values, etc. in four marine test stations, including Qingdao, Zhoushan, Xiamen, and Yulin, are modelled monthly using a statistical analysis technique. Normal distribution, logarithmic normal distribution, Weibull distribution, and uniform distribution of the samples are checked by the Shapiro-Wilk and Kolmogorov-Smirnov methods. Subsequently, the probability distribution function, the expected population value and variance, and the confidence interval are estimated. Corrosion data for twenty-two kinds of carbon steels, low alloy steels, and stainless steels, including A3, 3C, 16Mn, 10CrMoAl, 1Cr18Ni9Ti, in atmospheric and marine test stations are analyzed. The main environmental factors for atmospheric and marine corrosion of each type of steel are determined by grey relational analysis. Subsequently, a predictive model incorporating the main corrosion environmental factors, exposure time, and corrosion rate is built by the BP artificial neural network. After the evolution of corrosion pit depth is predicted by the artificial neural network, a fracture mechanics calculation is used to evaluate the residual life of a structure with corrosion pit defects.

  10. Simulation study on insoluble granular corrosion products deposited in PWR core

    International Nuclear Information System (INIS)

    Yang Xu; Zhou Tao; Ru Xiaolong; Lin Daping; Fang Xiaolu

    2014-01-01

    In the operation of reactor, such as fuel rods, reactor vessel internals etc. will be affected by corrosion erosion of high pressure coolant. It will produce many insoluble corrosion products. The FLUENT software is adopted to simulate insoluble granular corrosion products deposit distribution in the reactor core. The fluid phase uses the standard model to predict the flow field in the channel and forecast turbulence variation in the near-wall region. The insoluble granular corrosion products use DPM (Discrete Phase Model) to track the trajectory of the particles. The discrete phase model in FLUENT follows the Euler-Lagrange approach. The fluid phase is treated as a continuum by solving the Navier-Stokes equations, while the dispersed phase is solved by tracking a large number of particles through the calculated flow field. Through the study found, Corrosion products particles form high concentration area near the symmetry, and the entrance section of the corrosion products particles concentration is higher than export section. Corrosion products particles deposition attached on large area for the entrance of the cladding, this will change the core neutron flux distribution and the thermal conductivity of cladding material, and cause core axial offset anomaly (AOA). Corrosion products particles dot deposit in the outlet of cladding, which can lead to pitting phenomenon in a sheath. Pitting area will cause deterioration of heat transfer, destroy the cladding integrity. In view of the law of corrosion products deposition and corrosion characteristics of components in the reactor core. this paper proposes regular targeted local cleanup and other mitigation measures. (authors)

  11. Corrosion Assessment of Candidate Materials for the SHINE Subcritical Assembly Vessel and Components FY15 Report

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, Steven J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-01-01

    In the previous report of this series, a literature review was performed to assess the potential for substantial corrosion issues associated with the proposed SHINE process conditions to produce 99Mo. Following the initial review, substantial laboratory corrosion testing was performed emphasizing immersion and vapor-phase exposure of candidate alloys in a wide variety of solution chemistries and temperatures representative of potential exposure conditions. Stress corrosion cracking was not identified in any of the exposures up to 10 days at 80°C and 10 additional days at 93°C. Mechanical properties and specimen fracture face features resulting from slow-strain rate tests further supported a lack of sensitivity of these alloys to stress corrosion cracking. Fluid velocity was found not to be an important variable (0 to ~3 m/s) in the corrosion of candidate alloys at room temperature and 50°C. Uranium in solution was not found to adversely influence potential erosion-corrosion. Potentially intense radiolysis conditions slightly accelerated the general corrosion of candidate alloys, but no materials were observed to exhibit an annualized rate above 10 μm/y.

  12. Monitoring internal corrosion in natural gas pipelines; Monitoracao da corrosao interna em gasodutos

    Energy Technology Data Exchange (ETDEWEB)

    Nobrega, Ana C.V.; Silva, Djalma R.; Pimenta, Gutemberg S. [Universidade Federal do Rio Grande do Norte, Natal, RN (Brazil); Barbosa, Andrea F.F. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    2003-07-01

    For susceptibilities to the corrosion of the pipelines and equipment made in carbon steel and used by the natural gas, it makes be necessary to identify the acting corrosive agents and monitoring them along time, controlling failures for internal corrosion. Also, of that process it origins the black powder (solid particles) that can not commit the structural integrity of the equipment, but it can also bring the company other implications very serious, like quality of the sold product, as well as stops due to blockages and wastes for erosion of the equipment. The monitoring methodology and control of the corrosion in field consisted of the use of corrosion test equipment, chemical characterization of samples of black powder and liquids and analysis of the operational data of processes and plants. Like this, it was identified for the gas pipeline in analysis the most responsible parameters for the corrosive action of the fluid, establishing a controlling methodology and operational actions to maintain the corrosion rates at safe levels and structural warranty of the same. (author)

  13. Corrosion calculations report for the safety assessment SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    millimetres. The corrosion depths from the different processes could not simply be summed up as their combination requires a far more detailed chemical analysis (as well as statistical analysis regarding the flow and sulphide distributions), but, even if they are cautiously added, the sum is still less than 5 mm. For the case of a partially eroded buffer, the probabilistic calculations show that corrosion could lead to penetration of the copper shell for on average less than one canister. Such corrosion extent only comes about for canisters experiencing the most unfavourable combinations of sulphide concentration and flow rates. The calculations give a span of number of failed canisters from zero to less than two penetrated canisters which covers uncertainties regarding the buffer erosion process, the variability in the hydrogeological DFN models and uncertainties in the assumed sulphide concentration distribution, as well as uncertainties in the conceptual model of corrosion geometry (the part of the copper surface that is corroded by the sulphide transported to the canister)

  14. Soil Erosion in Britain: Updating the Record

    Directory of Open Access Journals (Sweden)

    John Boardman

    2013-08-01

    Full Text Available Concern about soil erosion on arable land in Britain dates back at least 40 years. Monitoring schemes and case studies have subsequently identified the areas at risk, the rates and frequencies and the major factors responsible for erosion. Initial concern focused on impacts on the farm and therefore on food production. Latterly the emphasis has shifted to off-farm impacts particularly reservoir sedimentation, muddy flooding of properties and the ecological damage to watercourses due to nutrient enrichment, pesticides and damage to fish spawning grounds from fine-sediment inputs. The shift has therefore been to concerns about a healthy and sustainable environment which includes soils. Government agencies, the water companies and the farming industry have lagged behind scientific studies in recognising and addressing erosion problems. Attempts at mitigation are now largely driven by the need to comply with the EU Water Framework Directive whereby watercourses must reach “good status” by 2015. Future changes in land use and climate will offer further challenges in terms of effective monitoring and compliance.

  15. Erosion yields of deposited beryllium layers

    International Nuclear Information System (INIS)

    Nishijima, D.; Doerner, R.P.; Baldwin, M.J.; De Temmerman, G.

    2009-01-01

    Erosion yields of various Be surfaces exposed to deuterium plasma, including polycrystalline Be (PC-Be), magnetron and thermionic vacuum arc deposited surfaces, and in situ plasma-deposited Be layers on Be (DP-Be/Be) and on graphite (DP-Be/C) targets, are measured in the linear divertor plasma simulator PISCES-B. It is observed that the enhanced erosion (∼3 times higher than PC-Be) of DP-Be/Be occurs at sample temperature T s ∼ 310 K, while DP-Be/Be possesses the same yield as PC-Be at a higher T s ∼ 570 K. The erosion yield of DP-Be/C is found to be slightly decreased at T s ∼ 850 K. This is consistent with the more effective formation of Be 2 C at higher T s , which has a higher surface binding energy than Be. It has been identified from spectroscopic measurements that Be is also eroded as BeD.

  16. Gully erosion in Madagascar: causes and impacts

    Science.gov (United States)

    Raveloson, Andrea; Székely, Balázs; Visnovitz, Ferenc

    2017-04-01

    Soil erosion has been recognized as the main cause of land degradation worldwide and gully erosion is currently considered as one of the most impressive and striking erosion type. This global environmental problem has numerous causes (both natural and anthropogenic) and inflict serious socio-economic problems all around the world. The present study aims to discuss the occurrence and environmental issues related to lavakization in Madagascar and its impact on landscape (badland formation), land use management, flora and fauna, infrastructures, soil properties and human life itself. We assembled and reviewed lavaka researches since 1953. Exact location of the field surveys, cited triggering factors and results of these scientific papers have been studied in detail and compared with our data collected using satellite imagery. Lavaka distribution was analyzed using GIS methods and the relation between their density and different factors was studied. An overview of the many contributing factors (climate, topography, geology, vegetation cover, fault systems, tectonism and land use including inappropriate cultivation and irrigation systems) is given in order to better understand lavaka formation, distribution and impacts. Synthesis of previous researches might help us define area susceptible to gully formation. This can be used to determine prevention priorities for farmers, to manage their lands sustainably. This is ILARG contribution 18.

  17. Survey of materials and corrosion performance in dry cooling applications

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, A.B.; Pratt, D.R.; Zima, G.E.

    1976-03-01

    The report presented summarizes aqueous and air-side corrosion aspects of candidate materials in dry cooling applications. The applications include piping, condensers, louvers, structures, and the air-cooled surfaces.

  18. Procedures for evaluating corrosion-inhibiting admixtures for structural concrete

    Science.gov (United States)

    2000-06-01

    The objectives of this research were to (1) develop procedures for evaluating and qualifying corrosion-inhibiting admixtures (CIAs) and (2) recommend performance criteria for their acceptance. Phase I work included a literature review of CIAs, the re...

  19. Multiple corrosion protection systems for reinforced concrete bridge components.

    Science.gov (United States)

    2007-07-01

    Eleven systems combining epoxy-coated reinforcement with another corrosion protection system are evaluated using : the rapid macrocell, Southern Exposure, cracked beam, and linear polarization resistance tests. The systems include : bars that are pre...

  20. The Relationship Between Corrosion and the Biological Sulfur Cycle

    National Research Council Canada - National Science Library

    Little, Brenda

    2000-01-01

    .... Sulfur and sulfur compounds, including sulfides, bisulfides, hydrogen sulfide (H2S), thiosulfates, polythionates and sulfuric acid, may be trapped or bound up in biofilms causing direct corrosion of materials...

  1. Effects of microbial redox cycling of iron on cast iron pipe corrosion in drinking water distribution systems.

    Science.gov (United States)

    Wang, Haibo; Hu, Chun; Zhang, Lili; Li, Xiaoxiao; Zhang, Yu; Yang, Min

    2014-11-15

    Bacterial characteristics in corrosion products and their effect on the formation of dense corrosion scales on cast iron coupons were studied in drinking water, with sterile water acting as a reference. The corrosion process and corrosion scales were characterized by electrochemical and physico-chemical measurements. The results indicated that the corrosion was more rapidly inhibited and iron release was lower due to formation of more dense protective corrosion scales in drinking water than in sterile water. The microbial community and denitrifying functional genes were analyzed by pyrosequencing and quantitative polymerase chain reactions (qPCR), respectively. Principal component analysis (PCA) showed that the bacteria in corrosion products played an important role in the corrosion process in drinking water. Nitrate-reducing bacteria (NRB) Acidovorax and Hydrogenophaga enhanced iron corrosion before 6 days. After 20 days, the dominant bacteria became NRB Dechloromonas (40.08%) with the protective corrosion layer formation. The Dechloromonas exhibited the stronger corrosion inhibition by inducing the redox cycling of iron, to enhance the precipitation of iron oxides and formation of Fe3O4. Subsequently, other minor bacteria appeared in the corrosion scales, including iron-respiring bacteria and Rhizobium which captured iron by the produced siderophores, having a weaker corrosion-inhibition effect. Therefore, the microbially-driven redox cycling of iron with associated microbial capture of iron caused more compact corrosion scales formation and lower iron release. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Corrosion Evaluation and Corrosion Control of Steam Generators

    Energy Technology Data Exchange (ETDEWEB)

    Maeng, W. Y.; Kim, U. C.; Sung, K. W.; Na, J. W.; Lee, Y. H.; Lee, D. H.; Kim, K. M

    2008-06-15

    Corrosion damage significantly influences the integrity and efficiency of steam generator. Corrosion problems of steam generator are unsolved issues until now even though much effort is made around world. Especially the stress corrosion cracking of heat exchange materials is the first issue to be solved. The corrosion protection method of steam generator is important and urgent for the guarantee of nuclear plant's integrity. The objectives of this study are 1) to evaluate the corrosion properties of steam generator materials, 2) to optimize the water chemistry of steam generator and 3) to develop the corrosion protection method of primary and secondary sides of steam generator. The results will be reflected to the water chemistry guideline for improving the integrity and efficiency of steam generator in domestic power plants.

  3. Corrosion Evaluation and Corrosion Control of Steam Generators

    International Nuclear Information System (INIS)

    Maeng, W. Y.; Kim, U. C.; Sung, K. W.; Na, J. W.; Lee, Y. H.; Lee, D. H.; Kim, K. M.

    2008-06-01

    Corrosion damage significantly influences the integrity and efficiency of steam generator. Corrosion problems of steam generator are unsolved issues until now even though much effort is made around world. Especially the stress corrosion cracking of heat exchange materials is the first issue to be solved. The corrosion protection method of steam generator is important and urgent for the guarantee of nuclear plant's integrity. The objectives of this study are 1) to evaluate the corrosion properties of steam generator materials, 2) to optimize the water chemistry of steam generator and 3) to develop the corrosion protection method of primary and secondary sides of steam generator. The results will be reflected to the water chemistry guideline for improving the integrity and efficiency of steam generator in domestic power plants

  4. Scanning reference electrode techniques in localized corrosion

    International Nuclear Information System (INIS)

    Isaacs, H.S.; Vyas, B.

    1979-04-01

    The principles, advantages, and implementations of scanning reference electrode techniques are reviewed. Data related to pitting, intergranular corrosion, welds and stress corrosion cracking are presented. The technique locates the position of localized corrosion and can be used to monitor the development of corrosion and changes in the corrosion rate under a wide range of conditions

  5. Corrosion control for low-cost reliability

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    This conference was held September 19-24, 1993 in Houston, Texas to provide a forum for exchange of state-of-the-art information on corrosion. Topics of interest focus on the following: atmospheric corrosion; chemical process industry corrosion; high temperature corrosion; and corrosion of plant materials. Individual papers have been processed separately for inclusion in the appropriate data bases

  6. Bentonite erosion - Laboratory studies

    International Nuclear Information System (INIS)

    Jansson, Mats

    2010-01-01

    Document available in extended abstract form only. Bentonite clay is proposed as buffer material in the KBS-3 concept of storing spent nuclear fuel. Since the clay is plastic it will protect the canisters containing the spent fuel from movements in the rock. Furthermore, the clay will expand when taking up water, become very compact and hence limit the transport of solutes to and from the canister to only diffusion. The chemical stability of the bentonite barrier is of vital importance. If much material would be lost the barrier will lose its functions. As a side effect, lots of colloids will be released which may facilitate radionuclide transport in case of a breach in the canister. There are scenarios where during an ice age fresh melt water may penetrate down to repository depths with relatively high flow rates and not mix with older waters of high salinity. Under such conditions bentonite colloids will be more stable and there is a possibility that the bentonite buffer would start to disperse and bentonite colloids be carried away by the passing water. This work is a part of a larger project called Bentonite Erosion, initiated and supported by SKB. In this work several minor experiments have been performed in order to investigate the influence of for instance di-valent cations, gravity, etc. on the dispersion behaviour of bentonite and/or montmorillonite. A bigger experiment where the real situation was simulated using an artificial fracture was conducted. Two Plexiglas slabs were placed on top of each other, separated by plastic spacers. Bentonite was placed in a container in contact with a fracture. The bentonite was water saturated before deionized water was pumped through the fracture. The evolution of the bentonite profile in the fracture was followed visually. The eluate was collected in five different slots at the outlet side and analyzed for colloid concentration employing Photon Correlation Spectroscopy (PCS) and a Single Particle Counter (SPC). Some

  7. Bentonite erosion. Laboratory studies

    Energy Technology Data Exchange (ETDEWEB)

    Jansson, Mats (Div. of Nuclear Chemistry, Royal Inst. of Technology, Stockholm (Sweden), School of Chemical Science and Engineering)

    2009-11-15

    This report covers the laboratory studies that have been performed at Nuclear Chemistry, KTH in the project 'Bentonite Erosion'. Many of the experiments in this report were performed to support the work of the modelling group and were often relatively simple. One of the experiment series was performed to see the impact of gravity and concentration of mono- and di-valent cations. A clay suspension was prepared in a test tube. A net was placed in contact with the suspension, the test tube was filled with solutions of different concentrations and the system was left overnight to settle. The tube was then turned upside down and the behaviour was visually observed. Either the clay suspension fell through the net or stayed on top. By using this method surprisingly sharp determinations of the Critical Coagulation (Flocculation) Concentration (CCC/CFC) could be made. The CCC/CFC of Ca2+ was for sodium montmorillonite determined to be between 1 and 2 mM. An artificial fracture was manufactured in order to simulate the real case scenario. The set-up was two Plexiglas slabs separated by 1 mm thick spacers with a bentonite container at one side of the fracture. Water was pumped with a very low flow rate perpendicular to bentonite container and the water exiting the fracture was sampled and analyzed for colloid content. The bentonite used was treated in different ways. In the first experiment a relatively montmorillonite rich clay was used while in the second bentonite where only the readily soluble minerals had been removed was used. Since Plexiglas was used it was possible to visually observe the bentonite dispersing into the fracture. After the compacted bentonite (1,000 kg/m3) had been water saturated the clay had expanded some 12 mm out into the fracture. As the experiment progressed the clay expanded more out into the fracture and seemed to fractionate in two different phases with less material in the outmost phase. A dark rim which was later analyzed to contain

  8. Corrosion studies on retrievable spent fuel containers: a progress report

    International Nuclear Information System (INIS)

    Ludemann, W.D.; Abrego, L.; McCright, R.D.

    1978-12-01

    Spent fuel canisters stored in halite (NaCl) deposits (salt beds) are subject to a severely corrosive environment when the hot brine inclusions, rich in calcium and magnesium chlorides, migrate to the canister. Since no data base exists on corrosion in halite brines, a survey was made of the corrosion resistance of potential canister materials in other concentrated brine environments. Corrosion-resistant metals include Ta, Ti Code 12, TiPd Alloy, Inconel 625, Hastelloy C-276, and Fe-base 29-4 Alloy. Although carbon steels have cost and availability advantages, they suffer from excessive corrosion rates in brines. Corrosion-resistant nonmetals include carbon, Teflon-type fluorocarbons, epoxide coatings, and polymer cements. While these materials are not suitable for constructing the canister, they could be used as a protective coating on a carbon steel canister. On the basis of this survey, we recommend a coated carbon steel canister, used with cathodic protection. It is important to start a test program to gather a data base on the corrosion of materials in halite brines and to verify the suitability of canister materials

  9. RECURRENT CORNEAL EROSION SYNDROME (a review

    Directory of Open Access Journals (Sweden)

    S. V. Trufanov

    2015-01-01

    Full Text Available Recurrent corneal erosion (RCE syndrome is characterized by episodes of recurrent spontaneous epithelial defects. Main clinical symptoms (pain, redness, photophobia, lacrimation occurred at night. Corneal lesions revealed by slit lamp exam vary depending on the presence of corneal epithelium raise, epithelial microcysts or epithelial erosions, stromal infiltrates and opacities. Microtraumas, anterior corneal dystrophies, and herpesvirus give rise to RCE. Other causes or factors which increase the risk of RCE syndrome include meibomian gland dysfunction, keratoconjunctivitis sicca, diabetes, and post-LASIK conditions. Basal membrane abnormalities and instability of epithelial adhesion to stroma play a key role in RCE pathogenesis. Ultrastructural changes in RCE include abnormalities of basal epithelial cells and epithelial basal membrane, absence or deficiency of semi-desmosomes, loss of anchor fibrils. Increase in matrix metalloproteinases and collagenases which contribute to basal membrane destruction results in recurrent erosions and further development of abnormal basal membrane. The goals of RCE therapy are to reduce pain (in acute stage, to stimulate re-epithelization, and to restore «adhesion complex» of basal membrane. In most cases, RCE responds to simple conservative treatment that includes lubricants, healing agents, and eye patches. RCEs that are resistant to simple treatment, require complex approach. Non-invasive methods include long-term contact lens use, instillations of autologous serum (eye drops, injections of botulinum toxin (induces ptosis, antiviral agent use or oral intake of metalloproteinase inhibitors. Cell membrane stabilizers, i.e., antioxidants, should be included into treatment approaches as well. Antioxidant effect of Emoxipine promotes tissue reparation due to the prevention of cell membrane lipid peroxidation as well as due to its anti-hypoxic, angioprotective, and antiplatelet effects. If conservative therapy

  10. Soil erosion in Slovene Istria

    Directory of Open Access Journals (Sweden)

    Matjaž Mikoš

    2009-12-01

    Full Text Available From the end of nineties of the 20th century, intense hydrologic and geomorphologic research is taking place in the Slovene Istria. As a part of this research also studies on soil erosion were undertaken in the period from 2005 to 2008. The field measurements were under taken onclosed 1m2 large erosion plots under three different land uses (on bare soils in an olive grove, on an overgrown meadow, in a forest, placed south of the Marezige village in the Rokava River basin.We show weekly measurements of surface erosion (interrill erosion for the period of 13 months (the end of March 2005 – the end of April 2006, as well as monthly and seasonal averages together with selected linear statistical correlations between soil erosion and weather parameters.From May 2005 to April 2006 the interrill erosion on bare soils in an olive grove with an inclination of 5.5° amounted to 9013 g/m2 (90 t/ha that corresponds to surface lowering rate of 8.5 mm/yr; on an overgrown meadow with an inclination of 9.4° it amounted to 168 g/m2 (1,68 t/ha that corresponds to surface lowering rate of 0.16 mm//yr; and in a forest with an inclination of 7.8° it amounted to 391 g/m2 (3,91 t/ha and in a forest with an inclination of 21.4° it amounted to 415 g/m2 (4,15 t/ha, respectively, that corresponds to surface lowering rate of 0.4 mm/yr.

  11. Review of synergisms in materials erosion due to multispecies impact

    International Nuclear Information System (INIS)

    Haasz, A.A.; Auciello, O.; Stangeby, P.C.

    1985-05-01

    Plasma-surface interaction phenomena have become a subject of major interest because of their relevance in two important technological developments of recent decades, viz, microelectronics and thermonuclear fusion. Microelectronic fabrication often involves the use of relatively low-pressure/low-temperature plasma discharges for etching micron-size features in integrated circuits; here erosion is a desired effect. Fusion plasmas, by contrast, cause erosion of the fusion device inner walls, which is generally not desirable. In both cases surfaces are bombarded simultaneously by plasma species which include ions, neutral atoms, electrons and photons, which might lead to enhanced erosion due to synergistic effects. Work performed to date suggests that similar chemistry may be involved in the erosion process associated with some semiconductor and fusion related materials: SiF 4 , SiCl 4 and CH 4 , are, for example, some of the principal species evolving from Si and C surfaces, when exposed to F, Cl and H atoms, respectively, causing the observed erosion. Considerable effort has been expended on studies involving synergistic effects for semiconductor fabrication. Research on synergism related to the erosion of fusion materials (C and carbon compounds) commenced comparatively recently; however, its importance has been increasingly recognized, and evidence of possible synergistic erosion of graphite has recently been obtained in the PLT fusion device. In light of the the interdisciplinary nature of the subject, experimental and theoretical work on synergistic effects in erosion of both semiconductors and fusion materials will be critically reviewed here in an attempt to unify concepts related to results and mechanisms proposed to explain the observed phenomena, and to explore possible new avenues of research. 128 refs

  12. A comparison of methods in estimating soil water erosion

    Directory of Open Access Journals (Sweden)

    Marisela Pando Moreno

    2012-02-01

    Full Text Available A comparison between direct field measurements and predictions of soil water erosion using two variant; (FAO and R/2 index of the Revised Universal Soil Loss Equation (RUSLE was carried out in a microcatchment o 22.32 km2 in Northeastern Mexico. Direct field measurements were based on a geomorphologic classification of the area; while environmental units were defined for applying the equation. Environmental units were later grouped withir geomorphologic units to compare results. For the basin as a whole, erosion rates from FAO index were statistical!; equal to those measured on the field, while values obtained from the R/2 index were statistically different from the res and overestimated erosion. However, when comparing among geomorphologic units, erosion appeared overestimate! in steep units and underestimated in more flat areas. The most remarkable differences on erosion rates, between th( direct and FAO methods, were for those units where gullies have developed, fn these cases, erosion was underestimated by FAO index. Hence, it is suggested that a weighted factor for presence of gullies should be developed and included in RUSLE equation.

  13. Surface erosion phenomena in connection with CTR applications

    International Nuclear Information System (INIS)

    Kaminsky, M.; Das, S.K.

    1976-01-01

    The interaction of plasma radiations with the exposed surfaces of components of plasma devices and future controlled thermonuclear fusion reactors (CTR) can cause a variety of surface effects. In turn, such surface effects can cause (a) the release of plasma contaminants, and (b) the damage and erosion of the irradiated surfaces. The contamination of the plasma can have serious effects on plasma stability and on plasma temperature, and the surface erosion can seriously limit the lifetime of the irradiated components. At present, knowledge of surface erosion rates for the plasma parameters and materials envisioned in CTR applications is only fragmentary. To what extent the erosion rates will be affected by synergistic effects due to the simultaneous bombardment of surfaces by high fluxes of energetic particles of various types and by photons is almost completely unknown. A summary of some of the major surface erosion phenomena which have been identified as being important for CTR applications by using single irradiation sources (e.g., accelerators) will be given. A discussion of some potential solutions to reduce surface erosion will be included. The main features of a recently completed two component irradiation facility at ANL for CTR related surface studies will be described

  14. Detection of simulated pitting corrosion and noises in crude oil storage tank by acoustic emission

    International Nuclear Information System (INIS)

    Shukri Mohd; Latif, N.A.; Azhar Mohd Sinin; Mohamad Daud; Abd Nasir Ibrahim

    2008-01-01

    The damage mechanisms associated with crude oil storage tanks can be complex and varied and include pitting corrosion due to presence of species such as sulphate reducing bacteria. Acoustic Emission (AE) could be used to characterise the pitting corrosion signal in crude oil storage tanks but it is extremely difficult to simulate the pitting corrosion in the laboratory using crude oil as electrolyte because crude oil is considered as non corrosive medium. In this study, induced current have been introduced onto a surface ASTM 516 steel as an electrical source to simulate the electrical noise produced during pitting corrosion process and AE sensor have been used to detect this current. It is found that AE system could detect AE signal release during current induction this current and is expected that if the exact simulation of the current magnitude produced during pitting corrosion process is made available, AE characterisation of pitting corrosion in such tank could be made possible. (Author)

  15. Development of an Accelerated Test Method for the Determination of Susceptibility to Atmospheric Corrosion

    Science.gov (United States)

    Ambrose, John R.

    1991-01-01

    The theoretical rationale is presented for use of a repetitive cyclic current reversal voltammetric technique for characterization of localized corrosion processes, including atmospheric corrosion. Applicability of this proposed experimental protocol is applied to characterization of susceptibility to crevice and pitting corrosion, atmospheric corrosion and stress corrosion cracking. Criteria upon which relative susceptibility is based were determined and tested using two iron based alloys commonly in use at NASA-Kennedy; A36 (a low carbon steel) and 4130 (a low alloy steel). Practicality of the procedure was demonstrated by measuring changes in anodic polarization behavior during high frequency current reversal cycles of 25 cycles per second with 1 mA/sq cm current density amplitude in solutions containing Cl anions. The results demonstrated that, due to excessive polarization which affects conductivity of barrier corrosion product layers, A36 was less resistant to atmospheric corrosion than its 4130 counterpart; behavior which was also demonstrated during exposure tests.

  16. Rainfall erosivity in Central Chile

    Science.gov (United States)

    Bonilla, Carlos A.; Vidal, Karim L.

    2011-11-01

    SummaryOne of the most widely used indicators of potential water erosion risk is the rainfall-runoff erosivity factor ( R) of the Revised Universal Soil Loss Equation (RUSLE). R is traditionally determined by calculating a long-term average of the annual sum of the product of a storm's kinetic energy ( E) and its maximum 30-min intensity ( I30), known as the EI30. The original method used to calculate EI30 requires pluviograph records for at most 30-min time intervals. Such high resolution data is difficult to obtain in many parts of the world, and processing it is laborious and time-consuming. In Chile, even though there is a well-distributed rain gauge network, there is no systematic characterization of the territory in terms of rainfall erosivity. This study presents a rainfall erosivity map for most of the cultivated land in the country. R values were calculated by the prescribed method for 16 stations with continuous graphical record rain gauges in Central Chile. The stations were distributed along 800 km (north-south), and spanned a precipitation gradient of 140-2200 mm yr -1. More than 270 years of data were used, and 5400 storms were analyzed. Additionally, 241 spatially distributed R values were generated by using an empirical procedure based on annual rainfall. Point estimates generated by both methods were interpolated by using kriging to create a map of rainfall erosivity for Central Chile. The results show that the empirical procedure used in this study predicted the annual rainfall erosivity well (model efficiency = 0.88). Also, an increment in the rainfall erosivities was found as a result of the rainfall depths, a regional feature determined by elevation and increasing with latitude from north to south. R values in the study area range from 90 MJ mm ha -1 h -1 yr -1 in the north up to 7375 MJ mm ha -1 h -1 yr -1 in the southern area, at the foothills of the Andes Mountains. Although the map and the estimates could be improved in the future by

  17. Riparian erosion vulnerability model based on environmental features.

    Science.gov (United States)

    Botero-Acosta, Alejandra; Chu, Maria L; Guzman, Jorge A; Starks, Patrick J; Moriasi, Daniel N

    2017-12-01

    included) has up to 30% probability to experience erosion greater than 1.0 m. By being able to identify the most vulnerable areas for stream and riparian sediment mobilization, conservation and management practices can be focused on areas needing the most attention and resources. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Corrosion aspects in steam generators of nuclear power plants

    International Nuclear Information System (INIS)

    Visoni, E.; Santos Pinto, M. dos

    1988-01-01

    Steam generators of pressurized water reactors (PWR), transfer heat from a primary coolant system to a secondary coolant system. Primary coolant water is heated in the core and passes through the steam generator that transfer heat to the secondary coolant water. However, the steam generator is dead for ionic impurities, corrosion products and fabrication/maintenence residues. These impurities concentrate between crevice and cracks. Many types of degradation mechanisms affect the tubes. The tubes are dented, craked, ovalized, wasted, etc. This paper describes the main corrosion problems in steam generators and includes the corrective actions to considered to reduce or eliminate these corrosion problems. (author) [pt

  19. The Corrosion Protection of Metals by Ion Vapor Deposited Aluminum

    Science.gov (United States)

    Danford, M. D.

    1993-01-01

    A study of the corrosion protection of substrate metals by ion vapor deposited aluminum (IVD Al) coats has been carried out. Corrosion protection by both anodized and unanodized IVD Al coats has been investigated. Base metals included in the study were 2219-T87 Al, 7075-T6 Al, Titanium-6 Al-4 Vanadium (Ti-6Al-4V), 4130 steel, D6AC steel, and 4340 steel. Results reveal that the anodized IVD Al coats provide excellent corrosion protection, but good protection is also achieved by IVD Al coats that have not been anodized.

  20. Microbiologically Influenced Corrosion

    Science.gov (United States)

    2009-01-01

    Aliphatic amines and nitrites used as corrosion inhibitors can be degraded by microorganisms, decreasing the effectiveness of the compounds and...workers (123) reported that silicone rubber dental liners could be degraded by yeasts. Moisture and chemical resistant polymeric coatings and...to be susceptible. 7.5. Concrete. Concrete is an inert aggregate, such as rock and gravel, surrounded by a cement binder. Concrete is a moderately

  1. Corrosion Protection of Aluminum

    Science.gov (United States)

    Dalrymple, R. S.; Nelson, W. B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred.

  2. Pipe Lines – External Corrosion

    Directory of Open Access Journals (Sweden)

    Dan Babor

    2008-01-01

    Full Text Available Two areas of corrosion occur in pipe lines: corrosion from the medium carried inside the pipes; corrosion attack upon the outside of the pipes (underground corrosion. Electrolytic processes are also involved in underground corrosion. Here the moisture content of the soil acts as an electrolyte, and the ions required to conduct the current are supplied by water-soluble salts (chlorides, sulfates, etc. present in the soil. The nature and amount of these soluble materials can vary within a wide range, which is seen from the varying electrical conductivity and pH (varies between 3 and 10. Therefore the characteristics of a soil will be an important factor in under-ground corrosion.

  3. Nuclear corrosion science and engineering

    CERN Document Server

    2012-01-01

    Understanding corrosion mechanisms, the systems and materials they affect, and the methods necessary for accurately measuring their incidence is of critical importance to the nuclear industry for the safe, economic and competitive running of its plants. This book reviews the fundamentals of nuclear corrosion. Corrosion of nuclear materials, i.e. the interaction between these materials and their environments, is a major issue for plant safety as well as for operation and economic competitiveness. Understanding these corrosion mechanisms, the systems and materials they affect, and the methods to accurately measure their incidence is of critical importance to the nuclear industry. Combining assessment techniques and analytical models into this understanding allows operators to predict the service life of corrosion-affected nuclear plant materials, and to apply the most appropriate maintenance and mitigation options to ensure safe long term operation. This book critically reviews the fundamental corrosion mechani...

  4. Corrosion inhibitors from expired drugs.

    Science.gov (United States)

    Vaszilcsin, Nicolae; Ordodi, Valentin; Borza, Alexandra

    2012-07-15

    This paper presents a method of expired or unused drugs valorization as corrosion inhibitors for metals in various media. Cyclic voltammograms were drawn on platinum in order to assess the stability of pharmaceutically active substances from drugs at the metal-corrosive environment interface. Tafel slope method was used to determine corrosion rates of steel in the absence and presence of inhibitors. Expired Carbamazepine and Paracetamol tablets were used to obtain corrosion inhibitors. For the former, the corrosion inhibition of carbon steel in 0.1 mol L(-1) sulfuric acid solution was about 90%, whereas for the latter, the corrosion inhibition efficiency of the same material in the 0.25 mol L(-1) acetic acid-0.25 mol L(-1) sodium acetate buffer solution was about 85%. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Corrosion of beryllium oxide

    International Nuclear Information System (INIS)

    Elston, J.; Caillat, R.

    1958-01-01

    Data are reported on the volatilization rate of beryllium oxide in moist air depending on temperature and water vapour concentration. They are concerned with powder samples or sintered shapes of various densities. For sintered samples, the volatilization rate is very low under the following conditions: - temperature: 1300 deg. C, - water vapour concentration in moist air: 25 g/m 3 , - flow rate: 12 I/hour corresponding to a speed of 40 m/hour on the surface of the sample. For calcinated powders (1300 deg. C), grain growth has been observed under a stream of moist air at 1100 deg. C. For instance, grain size changes from 0,5 to at least 2 microns after 500 hours of exposure at this temperature. Furthermore, results data are reported on corrosion of sintered beryllium oxide in pressurized water. At 250 deg. C, under a pressure of 40 kg/cm 2 water is very slightly corrosive; however, internal strains are revealed. Finally, some features on the corrosion in liquid sodium are exposed. (author) [fr

  6. Corrosion of fuel assembly materials

    International Nuclear Information System (INIS)

    Noe, M.; Frejaville, G.; Beslu, P.

    1985-08-01

    Corrosion of zircaloy-4 is reviewed in relation with previsions of improvement in PWRs performance: higher fuel burnup; increase coolant temperature, implying nucleate boiling on the hot clad surfaces; increase duration of the cycle due to load-follow operation. Actual knowledge on corrosion rates, based partly on laboratory tests, is insufficient to insure that external clad corrosion will not constitute a limitation to these improvements. Therefore, additional testing within representative conditions is felt necessary [fr

  7. Testing methodologies for corrosion fatigue

    OpenAIRE

    Delmotte, Edward; Micone, Nahuel; De Waele, Wim

    2015-01-01

    Offshore constructions are subjected to cyclic loading conditions. This situation is combined with the corrosive nature of the surrounding environment. It is of actual concern whether the combined effect is more damaging or not than the superposition of each effect independently. This literature review first introduces the reader to corrosion fatigue. Thereafter a critical comparison of some typical lab-scale fatigue corrosion test setups is given. Special emphasis is devoted to the instru...

  8. Corrosion problems of power engineering

    International Nuclear Information System (INIS)

    1989-01-01

    The proceedings contain 26 contributions, out of which 11 have been inputted in INIS. These are concerned with methods for the evaluation of corrosion resistance of materials for the nuclear industry, with examination of the corrosion behavior of composite overlays and of steels after the action of decontamination solutions, and with theoretical models of crack propagation. Corrosion problems of steam turbines, steam generator tubes and thermocouple bushings are discussed. (M.D.). 28 figs., 8 tabs., 63 refs

  9. Présentation des phénomènes de corrosion et des différents moyens de lutte disponibles. Description of Corrosion Phenomena and Different Ways of Combating Them.

    Directory of Open Access Journals (Sweden)

    Crolet J. L.

    2006-11-01

    Full Text Available Cet article donne une présentation générale des phénomènes de corrosion des matériaux métalliques. II s'attache à montrer comment les moyens de lutte contre la corrosion découlent très naturellement de la bonne compréhension de ces phénomènes.Les aspects électrochimiques, indispensables pour cette compréhension, sont présentés de manière aussi directe et brève que possible. Les divers modes de résistance à la corrosion sont décrits, qu'il s'agisse de modes a naturels » comme l'inertie chimique, la passivité, la pseudo-passivité ou les couches de patine, ou bien encore de modes a provoqués » comme le contrôle du milieu corrosif, l'inhibition, la protection cathodique ou la protection par revêtement.Enfin, les principales interactions entre effets mécaniques et corrosion sont abordées, et en particulier l'érosion-corrosion et la fragilisation par H.S. Des conjugaisons de phénomènes comme la corrosion galvanique, la corrosion inter-granulaire, la corrosion bactérienne sont également présentées. This article gives a general description of corrosion phenomena affecting metallic materials. It attempts ta show how corrosion control and prevention methods quite naturally require a good understanding of these phenomena.The electrochemical aspects indispensable for this understanding are described as directly and briefly as possible.Various types of corrosion resistance are described, whether concerning a natural » types such as chemical inertia, passivity, pseudo-passivity or patina loyers, or else c induced types » such as contrat of the corrosive medium, inhibition, cathodic protec-tion or protection by coating.The principal` interactions between mechanical effects and corrosion are taken up, and especially erosion corrosion and H2S embrittlement. Combinations of pheno-mena are also described, such as galvanic corrosion, intergranular corrosion and bacterial corrosion.

  10. The corrosion of depleted uranium in terrestrial and marine environments

    International Nuclear Information System (INIS)

    Toque, C.; Milodowski, A.E.; Baker, A.C.

    2014-01-01

    Depleted Uranium alloyed with titanium is used in armour penetrating munitions that have been fired in a number of conflict zones and testing ranges including the UK ranges at Kirkcudbright and Eskmeals. The study presented here evaluates the corrosion of DU alloy cylinders in soil on these two UK ranges and in the adjacent marine environment of the Solway Firth. The estimated mean initial corrosion rates and times for complete corrosion range from 0.13 to 1.9 g cm −2 y −1 and 2.5–48 years respectively depending on the particular physical and geochemical environment. The marine environment at the experimental site was very turbulent. This may have caused the scouring of corrosion products and given rise to a different geochemical environment from that which could be easily duplicated in laboratory experiments. The rate of mass loss was found to vary through time in one soil environment and this is hypothesised to be due to pitting increasing the surface area, followed by a build up of corrosion products inhibiting further corrosion. This indicates that early time measurements of mass loss or corrosion rate may be poor indicators of late time corrosion behaviour, potentially giving rise to incorrect estimates of time to complete corrosion. The DU alloy placed in apparently the same geochemical environment, for the same period of time, can experience very different amounts of corrosion and mass loss, indicating that even small variations in the corrosion environment can have a significant effect. These effects are more significant than other experimental errors and variations in initial surface area. -- Highlights: ► In-situ experiments were conducted to evaluate corrosion rates of depleted uranium. ► Samples were corroded in marine sediments, open sea water and two terrestrial soils. ► The depleted uranium titanium alloy corroded fastest in the marine environments. ► Rates of mass loss can vary through time if corrosion products are not removed.

  11. Corrosion of barrier materials in seawater environments

    Energy Technology Data Exchange (ETDEWEB)

    Heiser, J.H.; Soo, P.

    1995-07-01

    A brief review has been carried out on the performance of barrier materials for low-level radioactive wastes in seawater environments. The environments include those for shallower coastal waters as well as the deep ocean (down to 3800 m). The review is mainly focused on metallic materials since they are the most common for seawater service and they have the largest data base. Information from the literature is usually pertinent to shallower coastal locations, but there is a valuable source of corrosion data obtained from several studies of metallic specimens exposed to ocean-bed conditions. In addition, the corrosion of carbon steel barriers has been evaluated for actual waste containers that were retrieved from previously-used disposal sites in the Atlantic and Pacific Oceans. Of the metallic materials studied, carbon steel showed the least corrosion resistance. Failure by non-uniform attack in a typical waste container could occur in as little as 25 y in some ocean environments ` Penetration by local attack, such as pitting and crevice corrosion resistance was also observed for more expensive materials such as low-alloy steels, stainless steels, titanium alloys, zirconium alloys, copper alloys, nickel alloys, aluminum alloys, and lead alloys.

  12. Corrosion assessment of dry fuel storage containers

    Energy Technology Data Exchange (ETDEWEB)

    Graves, C.E.

    1994-09-01

    The structural stability as a function of expected corrosion degradation of 75 dry fuel storage containers located in the 200 Area Low-Level Waste Burial Grounds was evaluated. These containers include 22 concrete burial containers, 13 55-gal (208-l) drums, and 40 Experimental Breeder Reactor II (EBR-II) transport/storage casks. All containers are buried beneath at least 48 in. of soil and a heavy plastic tarp with the exception of 35 of the EBR-II casks which are exposed to atmosphere. A literature review revealed that little general corrosion is expected and pitting corrosion of the carbon steel used as the exterior shell for all containers (with the exception of the concrete containers) will occur at a maximum rate of 3.5 mil/yr. Penetration from pitting of the exterior shell of the 208-l drums and EBR-II casks is calculated to occur after 18 and 71 years of burial, respectively. The internal construction beneath the shell would be expected to preclude containment breach, however, for the drums and casks. The estimates for structural failure of the external shells, large-scale shell deterioration due to corrosion, are considerably longer, 39 and 150 years respectively for the drums and casks. The concrete burial containers are expected to withstand a service life of 50 years.

  13. Corrosion of barrier materials in seawater environments

    International Nuclear Information System (INIS)

    Heiser, J.H.; Soo, P.

    1995-07-01

    A brief review has been carried out on the performance of barrier materials for low-level radioactive wastes in seawater environments. The environments include those for shallower coastal waters as well as the deep ocean (down to 3800 m). The review is mainly focused on metallic materials since they are the most common for seawater service and they have the largest data base. Information from the literature is usually pertinent to shallower coastal locations, but there is a valuable source of corrosion data obtained from several studies of metallic specimens exposed to ocean-bed conditions. In addition, the corrosion of carbon steel barriers has been evaluated for actual waste containers that were retrieved from previously-used disposal sites in the Atlantic and Pacific Oceans. Of the metallic materials studied, carbon steel showed the least corrosion resistance. Failure by non-uniform attack in a typical waste container could occur in as little as 25 y in some ocean environments ' Penetration by local attack, such as pitting and crevice corrosion resistance was also observed for more expensive materials such as low-alloy steels, stainless steels, titanium alloys, zirconium alloys, copper alloys, nickel alloys, aluminum alloys, and lead alloys

  14. Corrosion and deposit evaluation in large diameter pipes using radiography

    International Nuclear Information System (INIS)

    Boateng, A.

    2012-01-01

    The reliability and safety of industrial equipment in the factories and processing industries are substantially influenced by degradation processes such as corrosion, erosion, deposits and blocking of pipes. These might lead to low production, unpredictable and costly shutdowns due to repair and replacement and sometimes combined environmental pollution and risk of personnel injuries. Only periodic inspection for the integrity of pipes and equipment can reduce the risk in connection with other maintenance activities. The research explored two methods of radiographic inspection techniques, the double wall technique and the tangential radiographic technique using Ir-192 for evaluating deposits and corrosion attacks across the inner and outer walls of steel pipes with diameter greater than 150 mm with or without insulation. The application of both techniques was conducted depending on pipe diameter, wall thickness, radiation source (Ir-92) and film combination. The iridium source was positioned perpendicular with respect to the pipe axis projecting the double wall of the pipe on the plated radiographic film. With the tangential radiographic technique, the source was placed tangential to the pipe wall and because of its large diameter, the source was collimated to prevent backscatter and also to focus the beam at the target area of interest. All measurements were performed on special designed test pieces to simulate corrosion attack and deposits on industrial pipes. Pitting corrosion measurements based on Tangential Radiographic Technique were more sophisticated, and therefore magnification factor and correction were used to establish the estimated pit depth on the film. The insulating material used to conserve the thermodynamic properties of the transported media had relatively negligible attenuation coefficient compared to the concrete deposit. The two explored techniques were successful in evaluating corrosion attack and deposit on the walls of the pipe and the risk

  15. Experiencies of corrosion and corrosion protection in seawater-cooling systems in the Nordic countries

    International Nuclear Information System (INIS)

    Henriksson, S.

    1984-10-01

    This report summarizes the experience of the corrosion resistance of pumps, heat exchangers, valves, and pipings in different seawater-cooling system. For pumps and heat exchangers the experience has been so extensive that a clear picture of todays status can be given. Owing to more scanty data concerning valves and pipes the survey of the corrosion in these components is less well substantiated. The most common pumps in the cooling systems of power stations are vertically extended shaft pumps. To counteract corrosion on column and casing with organic surface coating and on stainless steel shafts and impellers under shutdown conditions, these should be provided with internal and external cathodic protection. The experience of tin and aluminium bronzes in impellers and shafts in such pumps has been so poor - erosion and cavitaion damage - that a change has usually been made to preferentially ferritic-austenitic Mo-alloyd stainless steels. The combination of stainless steel/Ni-Resist 2 D has been found unsatisfactory owing to the occurrence of galvanic corrosion on the latter material. For heat exchangers, titanium has proved to be far and away the best choice. In the optimal blanket solution for a titanium heat exchangers the tubes are seal-welded to tube sheets of explosion-bonded titanium clad steel. For retubing of old condensers a similar procedure with tubes of high-alloy stainless steel in tube sheets of stainless clad steel is of economic interest. The effect of chlorination of the cooling water, however, remains to be clarified before such a procedure can be unreservedly recommended. Pipings of rubber-lined carbon steel or with thick coatings of solvent-free opoxy resin have shown very good corrosion resistance. Tar-epoxy-resin-coated pipes, however, should usually be provided with internal cathodic protection. Cement-lined carbon steel pipes are used with varying results in the offshore industry. Recently, however, pipes of the high slloy stainless steel

  16. Corrosion of Ultrasonic spot Welded Joints of Magnesium to Steel

    Science.gov (United States)

    Pan, Tsung-Yu; Santella, Michael L.

    Mixed-metal joining, especially between magnesium and steel, is one of the critical technologies in achieving light-weighting vehicle body construction. However, galvanic corrosion between mixed metal joints is inevitable but not well quantified. In this study, 1.6 mm thick Mg AZ31B-H24 was joined to 0.8 mm thick hot-dipped galvanized (HDG) mild steel by ultrasonic spot welding in lap-shear configuration. No specific corrosion protection was applied in order to study worst-case conditions for corrosion behavior. The approach used an automotive cyclic corrosion test — Ford Arizona Proving Ground Equivalent Corrosion Cycle (APGE), which includes cycles of dipping in a salt bath, air drying, then holding in constant humidity environment. Lap-shear strength of the joints decreased linearly with the exposure cycles. All the joints were either taken out of test cycle for mechanical test or they separated within the humidity chamber before 25th cycle. X-ray diffraction analysis confirmed the formation of Mg(OH)2 deposit in the crevice between the AZ31 and steel sheets and on the surface of the AZ31. The deposit grew thicker with cycles with exerting enough force to deform the AZ31 and HDG steel and causing a gradual opening of joints. The corrosion of the AZ31 was localized and nonuniform. The most severe corrosion occurred not at the intersection of AZ31 and the steel but rather 15-20 mm away from the spot welds.

  17. Task E container corrosion studies: Annual report. Revision 1

    International Nuclear Information System (INIS)

    Bunnell, L.R.; Doremus, L.A.; Topping, J.B.; Duncan, D.R.

    1994-06-01

    The Pacific Northwest Laboratory is conducting the Solid Waste Technology Support Program (SWTSP) for Westinghouse Hanford Company (WHC). Task E is the Container Corrosion Study Portion of the SWTSP that will perform testing to provide defensible data on the corrosion of low-carbon steel, as used in drums to contain chemical and radioactive wastes at the Hanford Site. A second objective of Task E is to provide and test practical alternative materials that have higher corrosion resistance than low-carbon steel. The scope of work for fiscal year (FY) 1993 included initial testing of mild steel specimens buried in Hanford soils or exposed to atmospheric corrosion in metal storage sheds. During FY 1993, progress was made in three areas of Task E. First, exposure of test materials began at the Soil Corrosion Test Site where low-carbon steel specimens were placed in the soil in five test shafts at depths of 9 m (30 ft). Second, the corrosion measurement of low-carbon steel in the soil of two solid waste trenches continued. The total exposure time is ∼ 500 days. Third, an atmospheric corrosion test of low-carbon steel was initiated in a metal shed (Building 2401-W) in the 200 West Area. This annual report describes the Task E efforts and provides a current status

  18. Corrosion Resistance of Copper Coatings Deposited by Cold Spraying

    Science.gov (United States)

    Winnicki, M.; Baszczuk, A.; Jasiorski, M.; Małachowska, A.

    2017-12-01

    In the article, a study of corrosion resistance of copper and copper-based cermet (Cu+Al2O3 and Cu+SiC) coatings deposited onto aluminum alloy substrate using the low-pressure cold spraying method is presented. The samples were subjected to two different corrosion tests at room temperature: (1) Kesternich test and (2) a cyclic salt spray test. The selected tests were allowed to simulate service conditions typical for urban, industrial and marine environment. Examination of corroded samples included analysis changes on the coating surface and in the microstructure. The physicochemical tests were carried out using x-ray diffraction to define corrosion products. Moreover, microhardness and electrical conductivity measurements were conducted to estimate mechanical and physical properties of the coatings after corrosion tests. XRD analysis clearly showed that regardless of corrosion conditions, for all samples cuprite (Cu2O) was the main product. However, in the case of Cu+Al2O3 cermet coating, chlorine- and sulfate-containing phases such as Cu2Cl(OH)3 (paracetamite) and Cu3(SO4)(OH)4 (antlerite) were also recorded. This observation gives better understanding of the lowest microstructure changes observed for Cu+Al2O3 coating after the corrosion tests. This is also a justification for the lowest decrease in electrical conductivity registered after the corrosion tests for this coating.

  19. Corrosion resistance of zinc-magnesium coated steel

    International Nuclear Information System (INIS)

    Hosking, N.C.; Stroem, M.A.; Shipway, P.H.; Rudd, C.D.

    2007-01-01

    A significant body of work exists in the literature concerning the corrosion behaviour of zinc-magnesium coated steel (ZMG), describing its enhanced corrosion resistance when compared to conventional zinc-coated steel. This paper begins with a review of the literature and identifies key themes in the reported mechanisms for the attractive properties of this material. This is followed by an experimental programme where ZMG was subjected to an automotive laboratory corrosion test using acidified NaCl solution. A 3-fold increase in time to red rust compared to conventional zinc coatings was measured. X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy were used to characterize the corrosion products formed. The corrosion products detected on ZMG included simonkolleite (Zn 5 Cl 2 (OH) 8 . H 2 O), possibly modified by magnesium uptake, magnesium hydroxide (Mg(OH) 2 ) and a hydroxy carbonate species. It is proposed that the oxygen reduction activity at the (zinc) cathodes is reduced by precipitation of alkali-resistant Mg(OH) 2 , which is gradually converted to more soluble hydroxy carbonates by uptake of atmospheric carbon dioxide. This lowers the surface pH sufficiently to allow thermodynamically for general precipitation of insoluble simonkolleite over the corroding surface thereby retarding the overall corrosion reactions, leaving only small traces of magnesium corrosion products behind. Such a mechanism is consistent with the experimental findings reported in the literature

  20. Review of the studies on fundamental issues in LBE corrosion

    Science.gov (United States)

    Zhang, Jinsuo; Li, Ning

    2008-02-01

    Lead bismuth eutectic (LBE) technology is being developed for applications in advanced nuclear systems and high-power spallation neutron targets. In this paper, the current understanding of corrosion and the fundamental issues relevant to corrosion when using LBE as a heavy liquid metal nuclear coolant are reviewed. Corrosion mechanisms and processes in LBE are examined. Prospective methods to mitigate corrosion are briefly surveyed. We then discuss the oxygen control technique for corrosion mitigation in detail, including the range of oxygen concentrations in LBE, oxygen sensors, and the surface oxidation kinetics. Existing experimental results are summarized and reviewed. Theoretical corrosion models for non-isothermal liquid metal loops are refined and compared each other. The applications of these models to a few practical lead-alloy systems are used to illustrate the corrosion mechanisms and the parameter dependency, and to benchmark. Based on the current state of knowledge, a number of R&D tasks are proposed to fill the gaps and firmly establish the scientific underpinning before LBE nuclear coolant technology is ready for programmatic and industrial applications.

  1. EUROCORR '87 - European corrosion meeting. 143rd event of the European Federation of Corrosion

    International Nuclear Information System (INIS)

    1987-01-01

    Corrosion and corrosion protection are of continuing importance both in conventional and modern technologies as well as in everyday life. In order to meet the demands in research, development and application EUROCORR provides a forum for the presentation and discussion of new work. EUROCORR '87 has been organized with substantial contributions from the Working Parties of the European Federation of Corrosion. Most of the topics are identical with the titles of the Working Parties and thus give a close insight into their activities and results. The volume contains the papers of the congress and includes the contributions of a special workshop. The content corresponds to the sequence of the scientific programme. (orig./IHOE)

  2. Seasonal variation and climate change impact in Rainfall Erosivity across Europe

    Science.gov (United States)

    Panagos, Panos; Borrelli, Pasquale; Meusburger, Katrin; Alewell, Christine; Ballabio, Cristiano

    2017-04-01

    Rainfall erosivity quantifies the climatic effect on water erosion and is of high importance for soil scientists, land use planners, agronomists, hydrologists and environmental scientists in general. The rainfall erosivity combines the influence of rainfall duration, magnitude, frequency and intensity. Rainfall erosivity is calculated from a series of single storm events by multiplying the total storm kinetic energy with the measured maximum 30-minute rainfall intensity. This estimation requests high temporal resolution (e.g. 30 minutes) rainfall data for sufficiently long time periods (i.e. 20 years). The European Commission's Joint Research Centr(JRC) in collaboration with national/regional meteorological services and Environmental Institutions made an extensive data collection of high resolution rainfall data in the 28 Member States of the European Union plus Switzerland to estimate rainfall erosivity in Europe. This resulted in the Rainfall Erosivity Database on the European Scale (REDES) which included 1,675 stations. The interpolation of those point erosivity values with a Gaussian Process Regression (GPR) model has resulted in the first Rainfall Erosivity map of Europe (Science of the Total Environment, 511: 801-815). In 2016, REDES extended with a monthly component, which allowed developing monthly and seasonal erosivity maps and assessing rainfall erosivity both spatially and temporally for European Union and Switzerland. The monthly erosivity maps have been used to develop composite indicators that map both intra-annual variability and concentration of erosive events (Science of the Total Environment, 579: 1298-1315). Consequently, spatio-temporal mapping of rainfall erosivity permits to identify the months and the areas with highest risk of soil loss where conservation measures should be applied in different seasons of the year. Finally, the identification of the most erosive month allows recommending certain agricultural management practices (crop

  3. Evaluation of steel corrosion by numerical analysis

    OpenAIRE

    Kawahigashi, Tatsuo

    2017-01-01

    Recently, various non-destructive and numerical methods have been used and many cases of steel corrosion are examined. For example, methods of evaluating corrosion through various numerical methods and evaluating macrocell corrosion and micro-cell corrosion using measurements have been proposed. However, there are few reports on estimating of corrosion loss with distinguishing the macro-cell and micro-cell corrosion and with resembling an actuality phenomenon. In this study, for distinguishin...

  4. Erosion and lateral surface processes

    Science.gov (United States)

    : Erosion can cause serious agricultural and environmental hazards. It can generate severe damage to the landscape, lead to significant loss of agricultural land and consequently to reduction in agricultural productivity, induce surface water pollution due to the transport of sediments and suspende...

  5. Relationship between sports drinks and dental erosion in 304 university athletes in Columbus, Ohio, USA.

    Science.gov (United States)

    Mathew, Tanya; Casamassimo, Paul S; Hayes, John R

    2002-01-01

    Acidic soft drinks, including sports drinks, have been implicated in dental erosion with limited supporting data in scarce erosion studies worldwide. The purpose of this study was to determine the prevalence of dental erosion in a sample of athletes at a large Midwestern state university in the USA, and to evaluate whether regular consumption of sports drinks was associated with dental erosion. A cross-sectional, observational study was done using a convenience sample of 304 athletes, selected irrespective of sports drinks usage. The Lussi Index was used in a blinded clinical examination to grade the frequency and severity of erosion of all tooth surfaces excluding third molars and incisal surfaces of anterior teeth. A self-administered questionnaire was used to gather details on sports drink usage, lifestyle, health problems, dietary and oral health habits. Intraoral color slides were taken of all teeth with erosion. Sports drinks usage was found in 91.8% athletes and the total prevalence of erosion was 36.5%. Nonparametric tests and stepwise regression analysis using history variables showed no association between dental erosion and the use of sports drinks, quantity and frequency of consumption, years of usage and nonsport usage of sports drinks. The most significant predictor of erosion was found to be not belonging to the African race (p sports drinks and dental erosion. Copyright 2002 S. Karger AG, Basel

  6. Estimation model of soil freeze-thaw erosion in Silingco watershed wetland of Northern Tibet.

    Science.gov (United States)

    Kong, Bo; Yu, Huan

    2013-01-01

    The freeze-thaw (FT) erosion is a type of soil erosion like water erosion and wind erosion. Limited by many factors, the grading evaluation of soil FT erosion quantities is not well studied. Based on the comprehensive analysis of the evaluation indices of soil FT erosion, we for the first time utilized the sensitivity of microwave remote sensing technology to soil moisture for identification of FT state. We established an estimation model suitable to evaluate the soil FT erosion quantity in Silingco watershed wetland of Northern Tibet using weighted summation method of six impact factors including the annual FT cycle days, average diurnal FT phase-changed water content, average annual precipitation, slope, aspect, and vegetation coverage. Finally, with the support of GIS, we classified soil FT erosion quantity in Silingco watershed wetland. The results showed that soil FT erosion are distributed in broad areas of Silingco watershed wetland. Different soil FT erosions with different intensities have evidently different spatial and geographical distributions.

  7. Remote sensing monitoring on soil erosion based on LUCC in Beijing mountain areas

    International Nuclear Information System (INIS)

    Gaiying, Chen

    2014-01-01

    The eco-environmental problems caused by land use and land cover change have been a severe block to regional sustainable development in the Beijing mountain areas. In this study, two temporal Landsat TM images in 2002 and 2009 were used, the soil erosion factors included vegetation coverage, slope and land use were calculated. The soil erosion degree was divided into six levels, micro, mild, moderate, strong, intensive and severe. The raster data with 30 m × 30 m pixels small-class of the soil erosion map was used to extract soil erosion information. This thesis evaluated soil erosion dynamic in Beijing mountain areas based on land use and land cover change with the combination of technologies and methodologies of multi-temporal satellite remote sensing, GIS and field investigation. The soil erosion change and their driving forces were analysed. The results showed micro and mild soil erosion mainly existed in the Beijing mountain areas. The moderate erosion emerged in the areas with both slope and poor vegetation cover. The strong, intensive and severe soil erosion were rare but distributed in mountainous areas in Huairou, Miyun, and Mentougou. The soil erosion situation has improved markedly due to environment management from 2002 to 2009

  8. Prevalence of dental erosion in 12-year-old schoolchildren of Lucknow city

    Directory of Open Access Journals (Sweden)

    Pooja Sinha

    2016-01-01

    Full Text Available Introduction: Dental erosion is tooth surface loss caused by chemical processes without bacterial involvement, which can affect children because of various dietary and other lifestyle factors. Aims: The aim of this study was to assess the prevalence of dental erosion in 12-year-old schoolchildren in Lucknow city. Materials and Methods: A total of 212 schoolchildren were selected through multistage cluster random sampling method. A pretested self-administered pro forma was used to record demographic data, medical history, and dietary habits. The clinical examination was done to evaluate dental erosion of children using dental erosion index by O'Sullivan. Descriptive analytical tests were used including distribution of erosion, its extent and severity. The findings were compared across the study participants using Chi-square test. Results: The overall prevalence of dental erosion was 34.12% with no significant sex difference. Dental erosion was significantly related to the frequency of consumption of fruit juices (67.07% followed by carbonated drinks (64.47%. In most of the cases, more than half of their surfaces were diagnosed as affected by erosion (26.25% central incisors, 4.83% lateral incisors. Conclusions: Dental erosion among the study group was found to be 34.12%, providing evidence that dental erosion is becoming a significant problem in Lucknow schoolchildren.

  9. Standard guide for corrosion-related failure analysis

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This guide covers key issues to be considered when examining metallic failures when corrosion is suspected as either a major or minor causative factor. 1.2 Corrosion-related failures could include one or more of the following: change in surface appearance (for example, tarnish, rust, color change), pin hole leak, catastrophic structural failure (for example, collapse, explosive rupture, implosive rupture, cracking), weld failure, loss of electrical continuity, and loss of functionality (for example, seizure, galling, spalling, swelling). 1.3 Issues covered include overall failure site conditions, operating conditions at the time of failure, history of equipment and its operation, corrosion product sampling, environmental sampling, metallurgical and electrochemical factors, morphology (mode) or failure, and by considering the preceding, deducing the cause(s) of corrosion failure. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibili...

  10. Predicting the future from the past in corrosion science and engineering

    Energy Technology Data Exchange (ETDEWEB)

    Macdonald, Digby D. [Center for Electrochemical Science and Technology, Department of Materials Science and Engineering, Pennsylvania State University, 201 Steidle Building, University Park, PA 16802 (United States); Engelhardt, George [OLI Systems Inc., 108 American Road, Morris Plains, NJ 07950 (United States)

    2004-07-01

    The accumulation of damage due to localized corrosion (pitting, stress corrosion cracking (SCC), corrosion fatigue (CF), crevice corrosion (CC), and erosion-corrosion (EC)) in complex industrial systems, such as power plants, refineries, desalination systems, etc., poses a threat to continued safe and economic operation, primarily because of the sudden, catastrophic nature of the resulting failures. Of particular interest in managing these forms of damage is the development of robust algorithms that can be used to predict the integrated damage as a function of time and as a function of the operating conditions of the system. Because complex systems of the same design rapidly become unique, due to differences in operating histories, and because failures are rare events, there is generally insufficient data on any given system to derive reliable empirical models that capture the impact of all (or even some) of the important independent variables. Accordingly, empirical models have generally failed to provide a robust basis for predicting the accumulation of corrosion damage in complex systems under realistic operating conditions. The alternative prediction philosophy is determinism, in which the development of damage is described in terms of valid, physico-electrochemical mechanisms with the output being constrained by the natural laws. The differential damage is then integrated along the corrosion evolutionary path for the system (i.e., over the future operating history) to yield the desired integrated damage, which is the quantity that is most useful to an operator. In this paper, we review the theory of predicting corrosion damage within the framework of Damage Function Analysis (DFA), with particular emphasis on the pitting of aluminum in chloride solutions and on the accumulation of damage from SCC in Type 304 SS components in the primary coolant circuits of Boiling Water (Nuclear) Reactors (BWRs). These cases have been selected to illustrate the various phases

  11. Effects of surface treatment on the cavitation erosion of high-chrome steel, zirconium, titanium and their alloys

    International Nuclear Information System (INIS)

    Marinin, V.G.

    1994-01-01

    The erosion resistance of some structural materials used for equipment components of the first and second circuits of NPPs is studied under cavitation created by an ultrasonic vibrator. It appears that after various thermomechanical treatments (programmed loading, low-temperature rolling) and coating deposition (titanium, zirconium and titanium nitride), the erosion resistance of the materials under consideration increases and the plasticity value is not notably modified. The titanium coatings deposited onto the steel increase the corrosion-fatigue resistance in a sodium chloride environment, in several cases

  12. Facilities Corrosion Impacts: When Corrosion Wins, the Mission Ends

    Science.gov (United States)

    2010-02-10

    Product/Results - Technology demonstrations and implementations at DoD Installations. - Cost and performance reports. - Recommendations for design ...guidance updates– ACSIM Installation Design Standards Payoff Service life extension of aging mission critical utilities and structures. Reduction in...corrosion.  Technology- Microcapsules in the form of microscopic spheres on the order of 50 to 150 microns in diameter containing corrosion-inhibiting

  13. Archaeological analogs and corrosion; Analogues archeologiques et corrosion

    Energy Technology Data Exchange (ETDEWEB)

    David, D

    2008-07-01

    In the framework of the high level and long life radioactive wastes disposal deep underground, the ANDRA built a research program on the material corrosion. In particular they aim to design containers for a very long time storage. Laboratory experiments are in progress and can be completed by the analysis of metallic archaeological objects and their corrosion after hundred years. (A.L.B.)

  14. Phytochemicals as Green Corrosion Inhibitors in Various Corrosive ...

    African Journals Online (AJOL)

    There is an intensive effort underway to develop new plant origin corrosion inhibitors for metal subjected to various environmental conditions. These efforts have been motivated by the desire to replace toxic inhibitors used for mitigation of corrosion of various metals and alloys in aqueous solutions. Plants represent a class ...

  15. phytochemicals as green corrosion inhibitors in various corrosive ...

    African Journals Online (AJOL)

    Mgina

    with aggressive environment is one among the acceptable practices used to reduce and/or prevent corrosion. ... may exhibit electrochemical activity such as corrosion inhibition (Davis et al. 2001). Some of their results ... zinc and copper in both HCl and H2SO4 acid solutions using gravimetric and polarization measurement ...

  16. Uncertainty in soil carbon accounting due to unrecognized soil erosion.

    Science.gov (United States)

    Sanderman, Jonathan; Chappell, Adrian

    2013-01-01

    The movement of soil organic carbon (SOC) during erosion and deposition events represents a major perturbation to the terrestrial carbon cycle. Despite the recognized impact soil redistribution can have on the carbon cycle, few major carbon accounting models currently allow for soil mass flux. Here, we modified a commonly used SOC model to include a soil redistribution term and then applied it to scenarios which explore the implications of unrecognized erosion and deposition for SOC accounting. We show that models that assume a static landscape may be calibrated incorrectly as erosion of SOC is hidden within the decay constants. This implicit inclusion of erosion then limits the predictive capacity of these models when applied to sites with different soil redistribution histories. Decay constants were found to be 15-50% slower when an erosion rate of 15 t soil ha(-1)  yr(-1) was explicitly included in the SOC model calibration. Static models cannot account for SOC change resulting from agricultural management practices focused on reducing erosion rates. Without accounting for soil redistribution, a soil sampling scheme which uses a fixed depth to support model development can create large errors in actual and relative changes in SOC stocks. When modest levels of erosion were ignored, the combined uncertainty in carbon sequestration rates was 0.3-1.0 t CO2  ha(-1)  yr(-1) . This range is similar to expected sequestration rates for many management options aimed at increasing SOC levels. It is evident from these analyses that explicit recognition of soil redistribution is critical to the success of a carbon monitoring or trading scheme which seeks to credit agricultural activities. © 2012 Blackwell Publishing Ltd.

  17. Modeling pore corrosion in normally open gold- plated copper connectors.

    Energy Technology Data Exchange (ETDEWEB)

    Battaile, Corbett Chandler; Moffat, Harry K.; Sun, Amy Cha-Tien; Enos, David George; Serna, Lysle M.; Sorensen, Neil Robert

    2008-09-01

    The goal of this study is to model the electrical response of gold plated copper electrical contacts exposed to a mixed flowing gas stream consisting of air containing 10 ppb H{sub 2}S at 30 C and a relative humidity of 70%. This environment accelerates the attack normally observed in a light industrial environment (essentially a simplified version of the Battelle Class 2 environment). Corrosion rates were quantified by measuring the corrosion site density, size distribution, and the macroscopic electrical resistance of the aged surface as a function of exposure time. A pore corrosion numerical model was used to predict both the growth of copper sulfide corrosion product which blooms through defects in the gold layer and the resulting electrical contact resistance of the aged surface. Assumptions about the distribution of defects in the noble metal plating and the mechanism for how corrosion blooms affect electrical contact resistance were needed to complete the numerical model. Comparisons are made to the experimentally observed number density of corrosion sites, the size distribution of corrosion product blooms, and the cumulative probability distribution of the electrical contact resistance. Experimentally, the bloom site density increases as a function of time, whereas the bloom size distribution remains relatively independent of time. These two effects are included in the numerical model by adding a corrosion initiation probability proportional to the surface area along with a probability for bloom-growth extinction proportional to the corrosion product bloom volume. The cumulative probability distribution of electrical resistance becomes skewed as exposure time increases. While the electrical contact resistance increases as a function of time for a fraction of the bloom population, the median value remains relatively unchanged. In order to model this behavior, the resistance calculated for large blooms has been weighted more heavily.

  18. Prediction of Soil Erosion Rates in Japan where Heavily Forested Landscape with Unstable Terrain

    Science.gov (United States)

    Nanko, K.; Oguro, M.; Miura, S.; Masaki, T.

    2016-12-01

    Soil is fundamental for plant growth, water conservation, and sustainable forest management. Multidisciplinary interest in the role of the soil in areas such as biodiversity, ecosystem services, land degradation, and water security has been growing (Miura et al., 2015). Forest is usually protective land use from soil erosion because vegetation buffers rainfall power and erosivity. However, some types of forest in Japan show high susceptibility to soil erosion due to little ground cover and steep slopes exceeding thirty degree, especially young Japanese cypress (Chamaecyparis obtusa) plantations (Miura et al., 2002). This is a critical issue for sustainable forest management because C. obtusaplantations account for 10% of the total forest coverage in Japan (Forestry Agency, 2009). Prediction of soil erosion rates on nationwide scale is necessary to make decision for future forest management plan. To predict and map soil erosion rates across Japan, we applied three soil erosion models, RUSLE (Revised Universal Soil Loss Equation, Wischmeier and Smith, 1978), PESERA (Pan-European Soil Erosion Risk Assessment, Kirkby et al., 2003), and RMMF (Revised Morgan-Morgan-Finney, Morgan, 2001). The grid scale is 1-km. RUSLE and PESERA are most widely used erosion models today. RMMF includes interactions between rainfall and vegetation, such as canopy interception and ratio of canopy drainage in throughfall. Evaporated rainwater by canopy interception, generally accounts for 15-20% in annual rainfall, does not contribute soil erosion. Whereas, larger raindrops generated by canopy drainage produced higher splash erosion rates than gross rainfall (Nanko et al., 2008). Therefore, rainfall redistribution process in canopy should be considered to predict soil erosion rates in forested landscape. We compared the results from three erosion models and analyze the importance of environmental factors for the prediction of soil erosion rates. This research was supported by the Environment

  19. Test methods for microbiologically influenced corrosion (MIC) in marine environments

    International Nuclear Information System (INIS)

    Little, B.; Wagner, P.; Mansfeld, F.

    1992-01-01

    Electrochemical techniques such as measurements of corrosion and redox potentials, polarization curves, polarization resistance, electrochemical impedance and electrochemical noise have been used to evaluate the impact of marine microorganisms on corrosion processes. Surface analytical techniques including microbiological culturing, scanning electron microscopy, microprobes and microelectrodes have been used to characterize metal surfaces after exposure to marine waters. A combination of electrochemical, surface analytical and microbiological techniques is the most promising approach for determining mechanisms of MIC

  20. Standard Operating Procedure for Accelerated Corrosion Testing at ARL

    Science.gov (United States)

    2017-11-01

    to scribe nonferrous materials so as to prevent contamination of the substrate during the process. The "X" scribe is made by scribing 2 intersecting...may include GMW14872 Cyclic Corrosion Testing (typically Exterior, Exposure C), ASTM B117 Neutral Salt Fog Testing, ASTM G50 Atmospheric Corrosion...using the same cleaning procedures, contamination of the substrate is minimized during the scribe process. All partners adhering to guidelines and

  1. Towards numerical prediction of cavitation erosion.

    Science.gov (United States)

    Fivel, Marc; Franc, Jean-Pierre; Chandra Roy, Samir

    2015-10-06

    This paper is intended to provide a potential basis for a numerical prediction of cavitation erosion damage. The proposed method can be divided into two steps. The first step consists in determining the loading conditions due to cavitation bubble collapses. It is shown that individual pits observed on highly polished metallic samples exposed to cavitation for a relatively small time can be considered as the signature of bubble collapse. By combining pitting tests with an inverse finite-element modelling (FEM) of the material response to a representative impact load, loading conditions can be derived for each individual bubble collapse in terms of stress amplitude (in gigapascals) and radial extent (in micrometres). This step requires characterizing as accurately as possible the properties of the material exposed to cavitation. This characterization should include the effect of strain rate, which is known to be high in cavitation erosion (typically of the order of several thousands s(-1)). Nanoindentation techniques as well as compressive tests at high strain rate using, for example, a split Hopkinson pressure bar test system may be used. The second step consists in developing an FEM approach to simulate the material response to the repetitive impact loads determined in step 1. This includes a detailed analysis of the hardening process (isotropic versus kinematic) in order to properly account for fatigue as well as the development of a suitable model of material damage and failure to account for mass loss. Although the whole method is not yet fully operational, promising results are presented that show that such a numerical method might be, in the long term, an alternative to correlative techniques used so far for cavitation erosion prediction.

  2. Modeling erosion from forest roads with WEPP

    Science.gov (United States)

    J. McFero Grace

    2007-01-01

    Forest roads can be major sources of soil erosion from forest watersheds. Sediments from forest roads are a concern due to their potential delivery to stream systems resulting in degradation of water quality. The Water Erosion Prediction Project (WEPP) was used to predict erosion from forest road components under different management practices. WEPP estimates are...

  3. Soil Erosion. LC Science Tracer Bullet.

    Science.gov (United States)

    Buydos, John F., Comp.

    Soil erosion is the detachment and movement of topsoil or soil material from the upper part of the soil profile. It may occur in the form of rill, gully, sheet, or wind erosion. Agents of erosion may be water, wind, glacial ice, agricultural implements, machinery, and animals. Soil conservation measures require a thorough understanding of the…

  4. Natural and anthropogenic rates of soil erosion

    Science.gov (United States)

    Regions of land that are brought into crop production from native vegetation typically undergo a period of soil erosion instability, and long term erosion rates are greater than for natural lands as long as the land continues being used for crop production. Average rates of soil erosion under natur...

  5. Soil erosion in humid regions: a review

    Science.gov (United States)

    Daniel J. Holz; Karl W.J. Williard; Pamela J. Edwards; Jon E. Schoonover

    2015-01-01

    Soil erosion has significant implications for land productivity and surface water quality, as sediment is the leading water pollutant worldwide. Here, erosion processes are defined. The dominant factors influencing soil erosion in humid areas are reviewed, with an emphasis on the roles of precipitation, soil moisture, soil porosity, slope steepness and length,...

  6. General Corrosion and Localized Corrosion of Waste Package Outer Barrier

    Energy Technology Data Exchange (ETDEWEB)

    K.G. Mon

    2004-10-01

    The waste package design for the License Application is a double-wall waste package underneath a protective drip shield (BSC 2004 [DIRS 168489]; BSC 2004 [DIRS 169480]). The purpose and scope of this model report is to document models for general and localized corrosion of the waste package outer barrier (WPOB) to be used in evaluating waste package performance. The WPOB is constructed of Alloy 22 (UNS N06022), a highly corrosion-resistant nickel-based alloy. The inner vessel of the waste package is constructed of Stainless Steel Type 316 (UNS S31600). Before it fails, the Alloy 22 WPOB protects the Stainless Steel Type 316 inner vessel from exposure to the external environment and any significant degradation. The Stainless Steel Type 316 inner vessel provides structural stability to the thinner Alloy 22 WPOB. Although the waste package inner vessel would also provide some performance for waste containment and potentially decrease the rate of radionuclide transport after WPOB breach before it fails, the potential performance of the inner vessel is far less than that of the more corrosion-resistant Alloy 22 WPOB. For this reason, the corrosion performance of the waste package inner vessel is conservatively ignored in this report and the total system performance assessment for the license application (TSPA-LA). Treatment of seismic and igneous events and their consequences on waste package outer barrier performance are not specifically discussed in this report, although the general and localized corrosion models developed in this report are suitable for use in these scenarios. The localized corrosion processes considered in this report are pitting corrosion and crevice corrosion. Stress corrosion cracking is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]).

  7. Erosion and deposition of metals and carbon in the DIII-D divertor

    International Nuclear Information System (INIS)

    Wampler, W.R.; Bastasz, R.; Buchenauer, D.

    1995-01-01

    Net erosion rates at the outer strike point of the DIII-D divertor plasma were measured for several materials during quiescent H-mode operation with deuterium plasmas. Materials examined include graphite, beryllium, tungsten, vanadium and molybdenum. For graphite, net erosion rates up to 4 nm/sec were found. Erosion rates for the metals were much smaller than for carbon. Ion fluxes from Langmuir probe measurements were used to predict gross erosion by sputtering. Measured net erosion was much smaller than predicted gross erosion. Transport of metal atoms by the plasma across the divertor surface was also examined. Light atoms were transported farther than heavy atoms as predicted by impurity transport models

  8. Corrosion of copper in alkaline chloride environments

    International Nuclear Information System (INIS)

    King, F.

    2002-08-01

    The available literature information on the corrosion and electrochemical behaviour of copper in alkaline environments has been reviewed. The purpose of the review was to assess the impact of an alkaline plume from cementitious material on the corrosion behaviour of a copper canister in an SKB-3 type repository. The effect of the evolution of the environmental conditions within the repository have been considered, including the effects of temperature, redox conditions, pore-water salinity and pH. If the pore-water pH increases prior to the establishment of anoxic conditions, the canister surface will passivate as the pore-water pH exceeds a value of ∼ pH 9. Passivation will result from the formation of a duplex Cu 2 O/Cu(OH) 2 film. The corrosion potential will be determined by the equilibrium potential for the Cu 2 O/Cu(OH) 2 couple under oxic conditions, or by the Cu/Cu 2 O redox couple under anoxic conditions (in the absence of sulphide). Pitting corrosion is only likely to occur early in the evolution of the repository environment, whilst the canister is still relatively cool ( 2 available to support localised corrosion, and prior to the increase in pore-water pH and salinity. The subsequent increase in canister surface temperature, pore-water pH and salinity, and decrease in O 2 will make pit initiation less likely, although the canister will remain passive provided the pore-water pH is maintained above pH 9. The higher the pore-water pH, the more strongly the canister is passivated and the less likely the surface is to undergo localised attack. If the pore-water salinity increases prior to the increase in pH, there could be a period of active canister corrosion before passivation occurs.Under these circumstances, the corrosion potential will be a true mixed potential, determine by the relative kinetics of Cu dissolution as CuCl 2 - and of the reduction of O 2 . The development of anoxic conditions and an increase in pore-water sulphide concentration will

  9. New technologies - new corrosion problems

    International Nuclear Information System (INIS)

    Heitz, E.

    1994-01-01

    Adequate resistance of materials to corrosion is equally important for classical and for new technologies. This article considers the economic consequences of corrosion damage and, in addition to the long-known GNP orientation, presents a new approach to the estimation of the costs of corrosion and corrosion protection via maintenance and especially corrosion-related maintenance. The significance of ''high-tech'', ''medium-tech'' and ''low-tech'' material and corrosion problems is assessed. Selected examples taken from new technologies in the areas of power engineering, environmental engineering, chemical engineering, and biotechnology demonstrate the great significance of the problems. It is concluded that corrosion research and corrosion prevention technology will never come to an end but will constantly face new problems. Two technologies are of particular interest since they focus attention on new methods of investigation: microelectronics and final disposal of radioactive wastes. The article closes by considering the importance of the transfer of experience and technology. Since the manufacturs and operators of machines and plant do not generally have access to the very latest knowledge, they should be kept informed through advisory services, experimental studies, databases, and further education. (orig.) [de

  10. corrosion inhibitor for carbon steels

    African Journals Online (AJOL)

    potentiodynamic polarisation techniques. It was found that. CNSL reduces the extent of the electrochemical processes taking place on carbon steel undergoing corrosion. The corrosion rate of the carbon steel was reduced by over 92 % when only 300 ppm of CNSL was applied. This indicates that. CNSL is a potential ...

  11. Tensammetric Studies on Corrosion Inhibitors

    Indian Academy of Sciences (India)

    Tensammetric Studies on Corrosion Inhibitors-I 277 paralleled potential data and corrosion data given in the next section. The only chemicals which bring about increased polarization of the steel speci- mens are sodium nitrite, dicyclohexylamine nitrite, cyclohexylamine and morpholine. The extent of polarization follows the ...

  12. Agricultural Polymers as Corrosion Inhibitors

    Science.gov (United States)

    Agricultural polymers were composed of extra-cellular polysaccharides secreted by Leuconostoc mesenteroides have been shown to inhibit corrosion on corrosion-sensitive metals. The substantially pure exopolysaccharide has a general structure consisting of alpha(1-6)-linked D-glucose backbone and appr...

  13. Corrosion monitoring on a large steel pressure vessel by thin-layer activation

    International Nuclear Information System (INIS)

    Wallace, G.; Boulton, L.H.; Hodder, D.

    1989-01-01

    Thin-layer activation (TLA) is a technique in which a surface is irradiated by a nuclear accelerator and thereby labeled with an accurate depth profile of low-level radioactivity. By monitoring this activity it is possible to calculate how much of that surface has been removed by corrosion. As the radioactivity is marked by the emission of penetrating gamma rays, it is possible to monitor this corrosion remotely through several centimeters of steel. This technique has been used to monitor erosion-corrosion occurring on the inner carbon steel wall of a continuous Kraft pulp digester at a paper mill. Representative coupons of the same steel as the digester wall were irradiated and fixed to the walls in the liquor extraction zone during a maintenance shutdown. The loss of metal over the six months was measured by external monitoring of gamma radiation through the vessel wall, and converted to a corrosion rate. Subsequent weight-loss measurements and comparison with ultrasonic thickness measurements established that the corrosion rate measured gave accurate results over a much shorter time scale. TLA thus enables current, rather than historical corrosion rates to be measured in a large steel pressure vessel

  14. Stainless steel corrosion in French LMFBR - Feedback and prevention against risks

    International Nuclear Information System (INIS)

    Grabon, V.; Brissonneau, L.; Billey, C.

    2015-01-01

    This paper deals with the mechanisms and the conditions leading to the most threatening corrosion risks specific to the use of sodium at high temperature as coolant in FBR (Fast Breeder Reactors) - apart from wastage (rapid erosion-corrosion of the steam generator tubes by sodium hydroxide due to steam-water leaks in sodium): Stress Corrosion Cracking (SCC) induced in sodium polluted by sodium hydroxide (following sodium-water reaction or incomplete cleaning of component), SCC induced by caustic solution during maintenance operations (cleaning of component or repair on drained sodium circuit inducing moist air ingress), and Intergranular Attack (IGA) induced on sensitized stainless steels by acid solutions used during maintenance operations (decontamination of component, chemical cleaning). These risks are illustrated by some examples of corrosion encountered through Phenix experience or in CEA sodium loops. The paper also describes the solutions and the preventive measures that have been put in place against these corrosion risks, in the form of design rules and operating procedures. Generally the plant operator cannot control the material parameters (metal composition, aging, stress) during the lifetime of the facility. Thus most of the time preventive measures consist in excluding at least one of the two other factors related to the chemical environment and/or to the operating conditions. Moreover corrosion of the primary components during cleaning and decontamination operations before repairing should be carefully examined to authorize their reuse in the reactor

  15. The Arctic Coastal Erosion Problem

    Energy Technology Data Exchange (ETDEWEB)

    Frederick, Jennifer M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Thomas, Matthew Anthony [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bull, Diana L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Craig A. [Integral Consulting Inc., San Francisco, CA (United States); Roberts, Jesse D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-09-01

    Permafrost-dominated coastlines in the Arctic are rapidly disappearing. Arctic coastal erosion rates in the United States have doubled since the middle of the twentieth century and appear to be accelerating. Positive erosion trends have been observed for highly-variable geomorphic conditions across the entire Arctic, suggesting a major (human-timescale) shift in coastal landscape evolution. Unfortunately, irreversible coastal land loss in this region poses a threat to native, industrial, scientific, and military communities. The Arctic coastline is vast, spanning more than 100,000 km across eight nations, ten percent of which is overseen by the United States. Much of area is inaccessible by all-season roads. People and infrastructure, therefore, are commonly located near the coast. The impact of the Arctic coastal erosion problem is widespread. Homes are being lost. Residents are being dispersed and their villages relocated. Shoreline fuel storage and delivery systems are at greater risk. The U.S. Department of Energy (DOE) and Sandia National Laboratories (SNL) operate research facilities along some of the most rapidly eroding sections of coast in the world. The U.S. Department of Defense (DOD) is struggling to fortify coastal radar sites, operated to ensure national sovereignty in the air, against the erosion problem. Rapid alterations to the Arctic coastline are facilitated by oceanographic and geomorphic perturbations associated with climate change. Sea ice extent is declining, sea level is rising, sea water temperature is increasing, and permafrost state is changing. The polar orientation of the Arctic exacerbates the magnitude and rate of the environmental forcings that facilitate coastal land area loss. The fundamental mechanics of these processes are understood; their non-linear combination poses an extreme hazard. Tools to accurately predict Arctic coastal erosion do not exist. To obtain an accurate predictive model, a coupling of the influences of

  16. Modelling soil carbon fate under erosion process in vineyard

    Science.gov (United States)

    Novara, Agata; Scalenghe, Riccardo; Minacapilli, Mario; Maltese, Antonino; Capodici, Fulvio; Borgogno Mondino, Enrico; Gristina, Luciano

    2017-04-01

    Soil erosion processes in vineyards beyond water runoff and sediment transport have a strong effect on soil organic carbon loss (SOC) and redistribution along the slope. The variation of SOC across the landscape determines a difference in soil fertility and vine productivity. The aim of this research was to study erosion of a Mediterranean vineyard, develop an approach to estimate the SOC loss, correlate the vines vigor with sediment and carbon erosion. The study was carried out in a Sicilian (Italy) vineyard, planted in 2011. Along the slope, six pedons were studied by digging 6 pits up to 60cm depth. Soil was sampled in each pedon every 10cm and SOC was analyzed. Soil erosion, detachment and deposition areas were measured by pole height method. The vigor of vegetation was expressed in term of NDVI (Normalized difference Vegetation Index) derived from a satellite image (RapidEye) acquired at berry pre-veraison stage (July) and characterized by 5 spectral bands in the shortwave region, including a band in the red wavelength (R, 630-685 nm) and in the near infrared (NIR, 760-850 nm) . Results showed that soil erosion, sediments redistribution and SOC across the hill was strongly affected by topographic features, slope and curvature. The erosion rate was 46Mg ha-1 y-1 during the first 6 years since planting. The SOC redistribution was strongly correlated with the detachment or deposition area as highlighted by pole height measurements. The approach developed to estimate the SOC loss showed that during the whole study period the off-farm SOC amounts to 1.6Mg C ha-1. As highlighted by NDVI results, the plant vigor is strong correlated with SOC content and therefore, developing an accurate NDVI approach could be useful to detect the vineyard areas characterized by low fertility due to erosion process.

  17. Electrochemical studies of corrosion inhibitors

    Science.gov (United States)

    Danford, M. D.

    1990-01-01

    The effect of single salts, as well as multicomponent mixtures, on corrosion inhibition was studied for type 1010 steel; for 5052, 1100, and 2219-T87 aluminum alloys; and for copper. Molybdate-containing inhibitors exhibit an immediate, positive effect for steel corrosion, but an incubation period may be required for aluminum before the effect of a given inhibitor can be determined. The absence of oxygen was found to provide a positive effect (smaller corrosion rate) for steel and copper, but a negative effect for aluminum. This is attributed to the two possible mechanisms by which aluminum can oxidize. Corrosion inhibition is generally similar for oxygen-rich and oxygen-free environments. The results show that the electrochemical method is an effective means of screening inhibitors for the corrosion of single metals, with caution to be exercised in the case of aluminum.

  18. Fatigue and Corrosion in Metals

    CERN Document Server

    Milella, Pietro Paolo

    2013-01-01

    This textbook, suitable for students, researchers and engineers, gathers the experience of more than 20 years of teaching fracture mechanics, fatigue and corrosion to professional engineers and running experimental tests and verifications to solve practical problems in engineering applications. As such, it is a comprehensive blend of fundamental knowledge and technical tools to address the issues of fatigue and corrosion. The book initiates with a systematic description of fatigue from a phenomenological point of view, since the early signs of submicroscopic damage in few surface grains and continues describing, step by step, how these precursors develop to become mechanically small cracks and, eventually, macrocracks whose growth is governed by fracture mechanics. But fracture mechanics is also introduced to analyze stress corrosion and corrosion assisted fatigue in a rather advanced fashion. The author dedicates a particular attention to corrosion starting with an electrochemical treatment that mechanical e...

  19. Corrosion Detection of Reinforcement of Building Materials with Piezoelectric Sensors

    Directory of Open Access Journals (Sweden)

    Jia Peng

    2017-06-01

    Full Text Available The extensive use of reinforced materials in the construction industry has raised increased concerns about their safety and durability, while corrosion detection of steel materials is becoming increasingly important. For the scientific management, timely repair and health monitoring of construction materials, as well as to ensure construction safety and prevent accidents, this paper investigates corrosion detection on construction materials based on piezoelectric sensors. At present, the commonly used corrosion detection methods include physical and electrochemical methods, but there are shortcomings such as large equipment area, low detection frequency, and complex operation. In this study an improved piezoelectric ultrasonic sensor was designed, which could not only detect the internal defects of buildings while not causing structural damage, but also realize continuous detection and enable qualitative and quantitative assessment. Corrosion detection of reinforced building materials with piezoelectric sensors is quick and accurate, which can find hidden dangers and provide a reliable basis for the safety of the buildings.

  20. Pitting corrosion resistant austenite stainless steel

    Science.gov (United States)

    van Rooyen, D.; Bandy, R.

    A pitting corrosion resistant austenite stainless steel comprises 17 to 28 wt. % chromium, 15 to 26 wt. % nickel, 5 to 8 wt. % molybdenum, and 0.3 to 0.5 wt. % nitrogen, the balance being iron, unavoidable impurities, minor additions made in the normal course of melting and casting alloys of this type, and may optionally include up to 10 wt. % of manganese, up to 5 wt. % of silicon, and up to 0.08 wt. % of carbon.

  1. Microstructural aspects of materials failure and corrosion

    International Nuclear Information System (INIS)

    Ferguson, I.F.

    1979-02-01

    Scanning and transmission electron microscopy, microprobe (electron, nuclear and Auger) analysis, X-ray diffraction and ferrography are applied to a wide range of problems of interest to the UKAEA. These include: the preparation of transistors, the coating of bearings, component reliability, the microstructure and behaviour of type 316 and other steels, the examination of the surface layers of various ceramics, steels and other alloys, as well as the corrosion of steels and Zircaloy. (author)

  2. Preventing erosion at pipeline crossings of watercourses

    International Nuclear Information System (INIS)

    Sawatsky, L.; Arnold, G.

    1997-01-01

    Watercourses are naturally vulnerable to erosion but the risk is particularly acute after sub-soil and armour materials have been disturbed by trenching and backfilling during construction. Various types of erosion (river scour, river bed, river channel bed and river bank ) and the progressive removal of pipeline cover resulting from erosion were discussed. Methods of estimating the risk of progressive erosion, river avulsions and beaver dam scour, and methods of mitigating erosion at pipeline crossings such as deep burial, proper siting, conventional armouring, and a combination of bank toe protection, and upper bank vegetation cover, were described

  3. Musculoskeletal ultrasound including definitions for ultrasonographic pathology

    DEFF Research Database (Denmark)

    Wakefield, RJ; Balint, PV; Szkudlarek, Marcin

    2005-01-01

    Ultrasound (US) has great potential as an outcome in rheumatoid arthritis trials for detecting bone erosions, synovitis, tendon disease, and enthesopathy. It has a number of distinct advantages over magnetic resonance imaging, including good patient tolerability and ability to scan multiple joint...

  4. Gully erosion in Moldova: evolution, importance and control

    Science.gov (United States)

    Leah, Tamara

    2017-04-01

    Soil erosion and landslides are major environmental problems in the Republic of Moldova, resulting in long-term impacts on land productivity and sustainable development of rural areas. Soil erosion occurs on about 1.5 million hectares of agricultural land. Erosion possible limits on agricultural land range from 3 t/ha to 180 t/ha. The weighted average in the country is 18.5 t/ ha/year. But once in 50-100 years the mentioned limits may be exceeded. Combination the physical-geographical complicate conditions with intensive agricultural activities on the slopes led to the development of linear (depth) erosion, from initial sheet and rills to entire systems of gullies and ravines. Depth erosion affects most powerful the slope land (60%) of southern steppe and central silvo-steppe zones of Moldova. Gullies refers to erosion forms named "agrierosional", which forms most often on slopes with a length of 500 m and inclination greater than 3°, pants occupied with vineyards and orchards. Annually on these slopes are formed 700-800 new gullies, with length of 50-70 km and an area of 300 hectares. As a result of the inadequate soil cultivation the gullies parameters are increased, that concentrates water runoff, intensifies soil erosion, forming corrugation on the soil surface and increase land and environment degradation. The first gullies inventory in Moldova was carried out in 1911, the following in 1965 and 1982. After this period their area was annual included in the land cadastral sheet. If in the 1911 the total number of gullies made up 9543 with an area of 14434 hectares, in 1965 was increased on average by 3.5 times and in the southern areas more than 10 times. Gullies density of the republic made up in 1911 - 0.42 unites/km2, in 1965 increased by 3 times and in some districts by 5-6 times. After 1965, a part of the land affected by gullies was gradually transformed from farmland into forest resources. This measure contributed to significant changes in agricultural

  5. Soil Erosion Threatens Food Production

    Directory of Open Access Journals (Sweden)

    Michael Burgess

    2013-08-01

    Full Text Available Since humans worldwide obtain more than 99.7% of their food (calories from the land and less than 0.3% from the oceans and aquatic ecosystems, preserving cropland and maintaining soil fertility should be of the highest importance to human welfare. Soil erosion is one of the most serious threats facing world food production. Each year about 10 million ha of cropland are lost due to soil erosion, thus reducing the cropland available for world food production. The loss of cropland is a serious problem because the World Health Organization and the Food and Agricultural Organization report that two-thirds of the world population is malnourished. Overall, soil is being lost from agricultural areas 10 to 40 times faster than the rate of soil formation imperiling humanity’s food security.

  6. Erosion in Mediterranean landscapes: Changes and future challenges

    Science.gov (United States)

    García-Ruiz, José M.; Nadal-Romero, Estela; Lana-Renault, Noemí; Beguería, Santiago

    2013-09-01

    Intense erosion processes are widespread in the Mediterranean region, and include sheet wash erosion, rilling, gullying, shallow landsliding, and the development of large and active badlands in both subhumid and semi-arid areas. This review analyses the main environmental and human features related to soil erosion processes, and the main factors that explain the extreme variability of factors influencing soil erosion, particularly recent land use changes. The importance of erosion in the Mediterranean is related to the long history of human activity in a region characterized by low levels of annual precipitation, the occurrence of intense rainstorms and long-lasting droughts, high evapotranspiration, the presence of steep slopes and the occurrence of recent tectonic activity, together with the recurrent use of fire, overgrazing and farming. These factors have resulted in a complex landscape in which intensification and abandonment, wealth and poverty can co-exist. The changing conditions of national and international markets and the evolution of population pressure are now the main drivers explaining land use changes, including farmland abandonment in mountain areas, the expansion of some subsidized crops to marginal lands, and the development of new terraces affected by landslides and intense soil erosion during extreme rainstorm events. The occurrence of human-related forest fires affecting thousands of hectares each year is a significant problem in both the northern and southern areas of the Mediterranean basin. Here, we highlight the rise of new scientific challenges in controlling the negative consequences of soil erosion in the Mediterranean region: 1) to reduce the effects and extent of forest fires, and restructure the spatial organization of abandoned landscapes; 2) to provide guidance for making the EU agricultural policy more adapted to the complexity and fragility of Mediterranean environments; 3) to develop field methods and models to improve the

  7. On inhibition of dental erosion.

    Science.gov (United States)

    Rölla, Gunnar; Jonski, Grazyna; Saxegaard, Erik

    2013-11-01

    To examine the erosion-inhibiting effect of different concentrations of hydrofluoric acid. Thirty-six human molars were individually treated with 10 ml of 0.1 M citric acid for 30 min (Etch 1), acid was collected and stored until analysis. The teeth were randomly divided into six groups and then individually treated with 10 ml of one of six dilutions (from 0.1-1%) of hydrofluoric acid. The teeth were then again treated with citric acid (Etch 2). The individual acid samples from Etch 1 and 2 were analyzed for calcium by flame atomic absorption spectroscopy and difference in calcium loss was calculated. The highest erosion inhibiting effect was obtained in groups with the highest concentrations of hydrofluoric acid, where the pH was lowest, below pKa of 3.17, thus the hydrofluoric acids being mainly in an undissociated state. Diluted hydrofluoric acid is present in aqueous solution of SnF2 and TiF4 (which are known to inhibit dental erosion): SnF2 + 3H2O = Sn(OH)2 + 2HF + H2O and TiF4 + 5H2O = Ti(OH)4 + 4HF + H2O. It is also known that pure, diluted hydrofluoric acid can inhibit dental erosion. Teeth treated with hydrofluoric acid are covered by a layer of CaF2-like mineral. This mineral is acid resistant at pH acid resistant mineral, initiated by tooth enamel treatment with hydrofluoric acid. Hydrofluoric acid is different in having fluoride as a conjugated base, which provides this acid with unique properties.

  8. Sports drinks and dental erosion.

    Science.gov (United States)

    Noble, Warden H; Donovan, Terence E; Geissberger, Marc

    2011-04-01

    Sports drinks were originally developed to improve hydration and performance in athletes taking part in intense or endurance sporting events. These drinks contain relatively high amounts of carbohydrates (sugars), salt, and citric acid. These ingredients create the potential for dental ramifications and overall public health consequences such as obesity and diabetes. High intake of sports drinks during exercise, coupled with xerostomia from dehydration, may lead to the possibility of erosive damage to teeth.

  9. Erosive forms in rivers systems

    International Nuclear Information System (INIS)

    Una Alvarez, E. de; Vidal Romani, J. R.; Rodriguez Martinez-Conde, R.

    2009-01-01

    The purpose of this work is to analyze the geomorphological meaning of the concepts of stability/change and to study its influence on a fluvial erosion system. Different cases of fluvial potholes in Galicia (NW of the Iberian Peninsula) are considered. The work conclusions refer to the nature of the process and its morphological evolution in order to advance towards later contributions with respect of this type of systems. (Author) 14 refs.

  10. The FSM technology -- Operational experience and improvements in local corrosion analysis

    International Nuclear Information System (INIS)

    Stroemmen, R.; Horn, H.; Gartland, P.O.; Wold, K.

    1996-01-01

    FSM (Field Signature Method) is a non-intrusive monitoring technique based on a patented principle, developed for the purpose of detection and monitoring of both general and localized corrosion, erosion and cracking in steel and metal structures, piping systems and vessels. Since 1991 FSM has been used for a wide range of applications e.g. for buried and open pipelines, process piping offshore, subsea pipelines and flowlines, applications in the nuclear power industry and in materials research in general. This paper describes typical applications of the FSM technology, and presents operational experience from some of the landbased and subsea installations. The paper also describes recent enhancements in the FSM technology and in the analysis of FSM readings, allowing for monitoring and detailed quantification of pitting and mesa corrosion, and of corrosion in welds

  11. Erosion behavior of EEDS cermet coatings

    International Nuclear Information System (INIS)

    Jin Guo; Xu Binshi; Wang Haidou; Yin Liang; Li Qingfen; Wei Shicheng; Cui Xiufang

    2008-01-01

    This paper investigates the erosion performance of electro-thermal explosion directional spraying (EEDS) cermet WC/Co coatings using an air solid particle erosion rig. The influences of the different parameters such as impact angle, impingement velocity, environment temperature, particle diameter, on the erosion property of the coatings were studied. The eroded surfaces were examined by scanning electron microscopy (SEM) equipped with energy dispersive spectrometry (EDS) and the erosion mechanisms were discussed. The structure and bond characters of the coatings were also determined by transmission electron microscopy (TEM), X-ray diffraction (XRD) and SEM. The results indicate that the EEDS WC/Co coatings are characterized by fine grain structure, good metallurgical bond and brittle erosion character. The erosion rates of the coatings decrease with temperature increasing and increase with impact angle and impingement velocity increasing. At elevated temperature, the oxidation happens on the coatings surface, which affects the erosion behavior

  12. Soil cover and wind erosion

    Energy Technology Data Exchange (ETDEWEB)

    Fryrear, D.W.

    Wind erosion on agricultural lands can be reduced if the soil surface is protected with crop residues. In evaluating the influence of residues on wind erosion, previous research has expressed residues of various crops as an equivalent of flat, small grain. This becomes difficult as the density of the residue changes with weathering, or as crops other than the major cultivated crops are grown. Soil losses due to wind erosion were determined by covering various percentages of the soil surface with simulated flat residues (wood dowels 3.1 to 25.4 mm in diameter). Covering 20% of the soil surface reduced soil losses 57%, and a 50% cover reduced soil losses 95%. The expression SLR = 1.81 e/sup x/ where x = /sup -0.072% SC/ describes the relationship between soil loss ratio (SLR) and percent soil cover (% SC) with a correlation coefficient of -0.94 (soil cover limits 8 to 80%). The cover can be any nonerodible material such as large clods, gravel, cotton gin trash, or any diameter stick between 3.1 and 25.4 mm. Percent soil cover is easily measured in the field or can be estimated with a minimum of training and experience.

  13. Container material for the disposal of highly radioactive wastes: corrosion chemistry aspects

    International Nuclear Information System (INIS)

    Grauer, R.

    1984-08-01

    Prior to disposal in crystalline formations it is planned to enclose vitrified highly radioactive waste from nuclear power plants in metallic containers ensuring their isolation from the groundwater for at least 1,000 years. Appropriate metals can be either thermodynamically stable in the repository environment (such as copper), passive materials with very low corrosion rates (titanium, nickel alloys), or metals such as cast iron or unalloyed cast steels which, although they corrode, can be used in sections thick enough to allow for this corrosion. The first part of the report presents the essentials of corrosion science in order to enable even a non-specialist to follow the considerations and arguments necessary to choose the material and design the container against corrosion. Following this, the principles of the long-term extrapolation of corrosion behaviour are discussed. The second part summarizes and comments upon the literature search carried out to identify published results relevant to corrosion in a repository environment. Results of archeaological studies are included wherever possible. Not only the general corrosion behaviour but also localized corrosion and stress corrosion cracking are considered, and the influence of hydrogen on the material behaviour is discussed. Taking the corrosion behaviour as criterion, the author suggests the use either of copper or of cast iron or steel as an appropriate container material. The report concludes with proposals for further studies. (Auth.)

  14. Experimental and Empirical Time to Corrosion of Reinforced Concrete Structures under Different Curing Conditions

    Directory of Open Access Journals (Sweden)

    Ahmed A. Abouhussien

    2014-01-01

    Full Text Available Reinforced concrete structures, especially those in marine environments, are commonly subjected to high concentrations of chlorides, which eventually leads to corrosion of the embedded reinforcing steel. The total time to corrosion of such structures may be divided into three stages: corrosion initiation, cracking, and damage periods. This paper evaluates, both empirically and experimentally, the expected time to corrosion of reinforced concrete structures. The tested reinforced concrete samples were subjected to ten alternative curing techniques, including hot, cold, and normal temperatures, prior to testing. The corrosion initiation, cracking, and damage periods in this investigation were experimentally monitored by an accelerated corrosion test performed on reinforced concrete samples. Alternatively, the corrosion initiation time for counterpart samples was empirically predicted using Fick’s second law of diffusion for comparison. The results showed that the corrosion initiation periods obtained experimentally were comparable to those obtained empirically. The corrosion initiation was found to occur at the first jump of the current measurement in the accelerated corrosion test which matched the half-cell potential reading of around −350 mV.

  15. MR imaging of erosions in interphalangeal joint osteoarthritis: is all osteoarthritis erosive?

    International Nuclear Information System (INIS)

    Grainger, A.J.; Farrant, J.M.; O'Connor, P.J.; Tan, A.L.; Emery, P.; Tanner, S.; McGonagle, D.

    2007-01-01

    Erosive osteoarthritis is usually considered as an inflammatory subset of osteoarthritis (OA). However, an inflammatory component is now recognised in all subsets of OA, so this subgroup of erosive or inflammatory OA is more difficult to conceptualise. The aim of this study was to compare routine CR and MRI to investigate erosion numbers and morphology to determine whether hand OA in general is a more erosive disease than previously recognised. Fifteen patients with clinical (OA) of the small joints of the hand underwent MRI of one of the affected proximal interphalangeal (PIP) or distal interphalangeal (DIP) joints. Conventional radiographs (CR) of the hand were also obtained. The MR images were reviewed by two observers for the presence of central and marginal erosions. The site and morphology of any erosions was recorded. CR images of the same hand joint were scored independently for central and marginal erosions by the same observers. There was 100% agreement between the observers for scoring erosions on CR. Agreement for the MRI scores was also excellent (kappa = 0.84). MRI detected 37 erosions, of which only 9 were seen on CR. The increase in sensitivity using MRI was much greater for marginal erosions (1 detected on CR, 19 on MRI) than for central erosions (8 on CR, 18 on MRI). Using MRI 80% of joints examined showed 1 or more erosions compared with 40% using CR. If only marginal erosions were considered 80% of joints were still considered erosive by MRI criteria, but only 1 showed evidence of erosion on CR. Morphologically central erosions appeared to represent areas of subchondral collapse and pressure atrophy. In contrast, marginal erosions resembled those seen in inflammatory arthritides. Erosions, and particularly marginal erosions typical of those seen in inflammatory arthritis, are a more common feature of small joint OA than conventional radiographs have previously indicated. (orig.)

  16. Numerical Analysis of Erosion Caused by Biomimetic Axial Fan Blade

    Directory of Open Access Journals (Sweden)

    Jun-Qiu Zhang

    2013-01-01

    Full Text Available Damage caused by erosion has been reported in several industries for a wide range of situations. In the present work, a new method is presented to improve the erosion resistance of machine components by biomimetic method. A numerical investigation of solid particle erosion in the standard and biomimetic configuration blade of axial fan is presented. The analysis consists in the application of the discrete phase model, for modeling the solid particles flow, and the Eulerian conservation equations to the continuous phase. The numerical study employs computational fluid dynamics (CFD software, based on a finite volume method. User-defined function was used to define wear equation. Gas/solid flow axial fan was simulated to calculate the erosion rate of the particles on the fan blades and comparatively analyzed the erosive wear of the smooth surface, the groove-shaped, and convex hull-shaped biomimetic surface axial flow fan blade. The results show that the groove-shaped biomimetic blade antierosion ability is better than that of the other two fan blades. Thoroughly analyze of antierosion mechanism of the biomimetic blade from many factors including the flow velocity contours and flow path lines, impact velocity, impact angle, particle trajectories, and the number of collisions.

  17. Improvement of PWR reliability by corrosion prevention

    International Nuclear Information System (INIS)

    Takamatsu, Hiroshi

    1999-01-01

    Since first PWR in Japan started commercial operation in 1970, we have encountered the various modes of corrosion on primary and secondary side components. We have paid much efforts for resolving these corrosion problems, that is, investigating the causes of corrosion and establishing the countermeasures for these corrosion. We summarize these efforts in this article. (author)

  18. Corrosion detection of nanowires by magnetic sensors

    KAUST Repository

    Kosel, Jürgen

    2017-10-05

    Disclosed are various embodiments related to a corrosion detection device for detecting corrosive environments. A corrosion detection device comprises a magnetic sensor and at least one magnetic nanowire disposed on the magnetic sensor. The magnetic sensor is configured to detect corrosion of the one or more magnetic nanowires based at least in part on a magnetic field of the one or more magnetic nanowires.

  19. A Multifunctional Coating for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott t.

    2011-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of existing microcapsulation designs, the corrosion controlled release function that triggers the delivery of corrosion indicators and inhibitors on demand, only when and where needed. Microencapsulation of self-healing agents for autonomous repair of mechanical damage to the coating is also being pursued. Corrosion indicators, corrosion inhibitors, as well as self-healing agents, have been encapsulated and dispersed into several paint systems to test the corrosion detection, inhibition, and self-healing properties of the coating. Key words: Corrosion, coating, autonomous corrosion control, corrosion indication, corrosion inhibition, self-healing coating, smart coating, multifunctional coating, microencapsulation.

  20. A probabilistic approach to modeling postfire erosion after the 2009 Australian bushfires

    Science.gov (United States)

    P. R. Robichaud; W. J. Elliot; F. B. Pierson; D. E. Hall; C. A. Moffet

    2009-01-01

    Major concerns after bushfires and wildfires include increased flooding, erosion and debris flows due to loss of the protective forest floor layer, loss of water storage, and creation of water repellent soil conditions. To assist postfire assessment teams in their efforts to evaluate fire effects and make postfire treatment decisions, a web-based Erosion Risk...

  1. A new in situ model to study erosive enamel wear, a clinical pilot study.

    NARCIS (Netherlands)

    Ruben, J.L.; Truin, G.J.; Bronkhorst, E.M.; Huysmans, M.C.D.N.J.M.

    2017-01-01

    OBJECTIVES: To develop an in situ model for erosive wear research which allows for more clinically relevant exposure parameters than other in situ models and to show tooth site-specific erosive wear effect of an acid challenge of orange juice on enamel. METHODS: This pilot study included 6

  2. Assessment of mercury erosion by surface water in Wanshan mercury mining area.

    Science.gov (United States)

    Dai, ZhiHui; Feng, Xinbin; Zhang, Chao; Shang, Lihai; Qiu, Guangle

    2013-08-01

    Soil erosion is a main cause of land degradation, and in its accelerated form is also one of the most serious ecological environmental problems. Moreover, there are few studies on migration of mercury (Hg) induced by soil erosion in seriously Hg-polluted districts. This paper selected Wanshan Hg mining area, SW China as the study area. Revised universal soil loss equation (RUSLE) and Geographic information system (GIS) methods were applied to calculate soil and Hg erosion and to classify soil erosion intensity. Our results show that the soil erosion rate can reach up to 600,884tkm(-2)yr(-1). Surfaces associated with very slight and extremely severe erosion include 76.6% of the entire land in Wanshan. Furthermore, the cumulative erosion rates in the area impacted by extremely severe erosion make up 90.5% of the total. On an annual basis, Hg surface erosion load was predicted to be 505kgyr(-1) and the corresponding mean migration flux of Hg was estimated to be 3.02kgkm(-2)yr(-1). The erosion loads of Hg resulting from farmland and meadow soil were 175 and 319kgyr(-1) respectively, which were enhanced compared to other landscape types due to the fact that they are generally located in the steep zones associated with significant reclamation. Contributing to establish a mass balance of Hg in Wanshan Hg mining area, this study supplies a dependable scientific basis for controlling soil and water erosion in the local ecosystems. Land use change is the most effective way for reducing Hg erosion load in Wanshan mining area. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Urethral Stricture Outcomes After Artificial Urinary Sphincter Cuff Erosion: Results From a Multicenter Retrospective Analysis.

    Science.gov (United States)

    Gross, Martin S; Broghammer, Joshua A; Kaufman, Melissa R; Milam, Douglas F; Brant, William O; Cleves, Mario A; Dum, Travis W; McClung, Christopher; Jones, LeRoy A; Brady, Jeffrey D; Pryor, Michael B; Henry, Gerard D

    2017-06-01

    To evaluate the influence of both repair type and degree of cuff erosion on postoperative urethral stricture rate. Sparse literature exists regarding patient outcomes after artificial urinary sphincter (AUS) cuff erosion. Surgeons from 6 high-volume male continence centers compiled a comprehensive database of post-erosion patients to examine outcomes. This retrospective multi-institution study included 80 patients treated for AUS cuff erosions. Seventy-eight patients had specific information regarding post-cuff erosion urethral strictures. Erosion patients were categorized into 1 of 3 repair types at the time of explant surgery: catheter only, single-layer capsule-to-capsule repair (urethrorrhaphy), and formal urethroplasty. Operative notes and available medical records were extensively reviewed to collect study data. Twenty-five of 78 patients manifested a urethral stricture after AUS cuff erosion (32%). More strictures occurred among patients who underwent urethrorrhaphy (40% vs 29% for catheter only and 14% for urethroplasty). Stricture rates did not vary significantly by repair type (P = .2). Strictures occurred significantly more frequently in patients with complete cuff erosions (58%) as compared to partial erosions (25%, P = .037). A trend was detected regarding increased percentage of erosion correlating with increased stricture rate, but this did not reach statistical significance (P = .057). Partially eroded patients were more likely to undergo urethrorrhaphy repair (60%, P = .002). Urethral stricture was more likely to occur after complete cuff erosion as opposed to partial erosion in this multicenter retrospective population. Repair type, whether catheter only, urethrorrhaphy, or formal urethroplasty, did not appear to influence postoperative stricture rate. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Long-term erosion rate measurements in gypsum caves of Sorbas (SE Spain) by the Micro-Erosion Meter method

    Science.gov (United States)

    Sanna, Laura; De Waele, Jo; Calaforra, José Maria; Forti, Paolo

    2015-01-01

    The present work deals with the results of long-term micro-erosion measurements in the most important gypsum cave of Spain, the Cueva del Agua (Sorbas, Almeria, SE Spain). Nineteen MEM stations were positioned in 1992 in a wide range of morphological and environmental settings (gypsum floors and walls, carbonate speleothems, dry conduits and vadose passages) inside and outside the cave, on gypsum and carbonate bedrocks and exposed to variable degree of humidity, different air flow and hydrodynamic conditions. Four different sets of stations have been investigated: (1) the main cave entrance (Las Viñicas spring); (2) the main river passage; (3) the abandoned Laboratory tunnel; and (4) the external gypsum surface. Data over a period of about 18 years are available. The average lowering rates vary from 0.014 to 0.016 mm yr- 1 near the main entrance and in the Laboratory tunnel, to 0.022 mm - 1 on gypsum floors and 0.028 mm yr- 1 on carbonate flowstones. The denudation data from the external gypsum stations are quite regular with a rate of 0.170 mm yr- 1. The observations allowed the collecting of important information concerning the feeding of the karst aquifer not only by infiltrating rainwater, but under present climate conditions also by water condensation of moist air flow. This contribution to the overall karst processes in the Cueva del Agua basin represents over 20% of the total chemical dissolution of the karst area and more than 50% of the speleogenetically removed gypsum in the cave system, thus representing all but a secondary role in speleogenesis. Condensation-corrosion is most active along the medium walls, being slower at the roof and almost absent close to the floor. This creates typical corrosion morphologies such as cupola, while gypsum flowers develop where evaporation dominates. This approach also shows quantitatively the morphological implications of condensation-corrosion processes in gypsum karst systems in arid zones, responsible for an

  5. Corrosion of steel structures in sea-bed sediment

    Indian Academy of Sciences (India)

    SBS corrosion has now become a serious problem in marine environment and an important issue in corrosion science. In this paper, approach in the field of SBS corrosion is reviewed. Electrochemical and microbial corrosion factors, corrosion mechanism, measurement of metal corrosion rate, corrosion evaluation and ...

  6. Atmospheric corrosion of mild steel

    Directory of Open Access Journals (Sweden)

    Morcillo, M.

    2011-10-01

    Full Text Available The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a the morphology of steel corrosion products and corrosion product layers; and b long-term atmospheric corrosion ( > 10 years.

    La corrosión atmosférica del acero suave es un tema de gran amplitud que ha sido tratado por muchos autores en numerosas regiones del mundo. Este artículo de compilación incorpora publicaciones relevantes sobre esta temática, en particular sobre la naturaleza de los productos de corrosión atmosférica, mecanismos y cinética de los procesos de corrosión atmosférica, prestando una atención especial a dos aspectos sobre los que la información publicada ha sido menos abundante: a morfología de los productos de corrosión del acero y capas de productos de corrosión, y b corrosión atmosférica a larga duración (> 10 años.

  7. Erosion Testing of Coatings for V-22 Aircraft Applications

    Directory of Open Access Journals (Sweden)

    G. Y. Richardson

    2003-01-01

    Full Text Available High-velocity (183 m/sec sand erosion tests in a wind tunnel were conducted to evaluate developmental coatings from three separate companies under funding by the Navy's phase I small business innovative research program. The purpose of the coatings was to address a particular problem the V-22 tilt-rotor aircraft (Osprey was having with regard to ingestion of sand particles by a titanium impeller that was associated with the aircraft's environmental control system. The three coatings that were deposited on titanium substrates and erosion-tested included (1 SixCy/DLC multilayers deposited by chemical vapor deposition (CVD; (2 WC/TaC/TiC processed by electrospark deposition; and (3 polymer ceramic mixtures applied by means of an aqueous synthesis. The erosion test results are presented; they provided the basis for assessing the suitability of some of these coatings for the intended application.

  8. Corrosive injuries of the upper gastrointestinal tract

    Directory of Open Access Journals (Sweden)

    Babu Lal Meena

    2017-01-01

    Full Text Available Corrosive injury of the upper gastrointestinal tract is a worldwide clinical problem, mostly occurring in children. Alkaline agents produce deeper injuries whereas acidic agents produce superficial injuries usually. Hoarseness, stridor, and respiratory distress indicate airway injury. Dysphagia, odynophagia, and drooling of saliva suggest esophageal injury whereas abdominal pain, nausea, and vomiting are indicative of stomach injury. X-rays should be done to rule out perforation. Endoscopy is usually recommended in the first 12–48 h although it is safe up to 96 h after caustic ingestion. Endoscopy should be performed with caution and gentle insufflation. Initial management includes getting intravenous access and replacement of fluids. Hyperemia and superficial ulcerations have excellent recovery while deeper injuries require total parenteral nutrition or feeding jejunostomy. Patients suspected of perforation should be subjected to laparotomy. Common complications after corrosive injury are esophageal stricture, gastric outlet obstruction, and development of esophageal and gastric carcinoma.

  9. Chemical cleaning of boilers and corrosion protection

    International Nuclear Information System (INIS)

    Elhosary, A.A.

    1993-01-01

    While being assembled and installed, thermal-power equipment accumulates a large amount of corrosion products, scale (as much as 350 g/m 2 ), welding residue, and other contaminants that must be removed before the equipment is started up. This is generally done with various acids and inhibitors. For boilers this chemical cleaning process is termed pre start cleaning. In contrast, an operational cleaning of boilers is also carried out, in order to remove carbonate deposits, that interfere with heat transfer, as well as the corrosion products that accumulate with use. The techniques include rinsing with water to remove contaminants not firmly adhering to the metal surfaces, decreasing in alkali reagents to remove grease and to loosen scale, pickling in mineral and organic acids for scale removal, and passivation of the metal surface. decreasing is usually carried out in alkali reagents used are caustic soda, soda ash, tri sodium phosphate ammonia, and surface-active agents

  10. Comparison of erosion and erosion control works in Macedonia, Serbia and Bulgaria

    Directory of Open Access Journals (Sweden)

    Ivan Blinkov

    2013-12-01

    Natural conditions in the Balkan countries contribute to the appearance of various erosion forms and the intensity of the erosion processes. Over the history of these countries, people who settled this region used the available natural resources to fill their needs (tree cutting, incorrect plugging, overgrazing, which contributed to soil erosion. Organized erosion control works in the Balkans started in the beginning of the 20th century (1905 in Bulgaria. The highest intensity of erosion control works were carried out during the period 1945 – 1990. Various erosion control works were launched. Bulgaria had a large anti-erosion afforestation, almost 1 million ha. Bulgaria's ecological river restoration approach has been in use for almost 50 years. Serbia contributed significant erosion and torrent control works on hilly agricultural areas. Specific screen barrages and afforestation on extremely dry areas are characteristic in Macedonia. A common characteristic for all countries is a high decrease in erosion control works in the last 20 years.

  11. Molybdate Coatings for Protecting Aluminum Against Corrosion

    Science.gov (United States)

    Calle, Luz Marina; MacDowell, Louis G.

    2005-01-01

    Conversion coatings that comprise mixtures of molybdates and several additives have been subjected to a variety of tests to evaluate their effectiveness in protecting aluminum and alloys of aluminum against corrosion. Molybdate conversion coatings are under consideration as replacements for chromate conversion coatings, which have been used for more than 70 years. The chromate coatings are highly effective in protecting aluminum and its alloys against corrosion but are also toxic and carcinogenic. Hexavalent molybdenum and, hence, molybdates containing hexavalent molybdenum, have received attention recently as replacements for chromates because molybdates mimic chromates in a variety of applications but exhibit significantly lower toxicity. The tests were performed on six proprietary formulations of molybdate conversion coatings, denoted formulations A through F, on panels of aluminum alloy 2024-T3. A bare alloy panel was also included in the tests. The tests included electrochemical impedance spectroscopy (EIS), measurements of corrosion potentials, scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS).

  12. High temperature corrosion of metals

    International Nuclear Information System (INIS)

    Quadakkers, W.J.; Schuster, H.; Ennis, P.J.

    1988-08-01

    This paper covers three main topics: 1. high temperature oxidation of metals and alloys, 2. corrosion in sulfur containing environments and 3. structural changes caused by corrosion. The following 21 subjects are discussed: Influence of implanted yttrium and lanthanum on the oxidation behaviour of beta-NiA1; influence of reactive elements on the adherence and protective properties of alumina scales; problems related to the application of very fine markers in studying the mechanism of thin scale formation; oxidation behaviour of chromia forming Co-Cr-Al alloys with or without reactive element additions; growth and properties of chromia-scales on high-temperature alloys; quantification of the depletion zone in high temperature alloys after oxidation in process gas; effects of HC1 and of N2 in the oxidation of Fe-20Cr; investigation under nuclear safety aspects of Zircaloy-4 oxidation kinetics at high temperatures in air; on the sulfide corrosion of metallic materials; high temperature sulfide corrosion of Mn, Nb and Nb-Si alloys; corrosion behaviour or NiCrAl-based alloys in air and air-SO2 gas mixtures; sulfidation of cobalt at high temperatures; preoxidation for sulfidation protection; fireside corrosion and application of additives in electric utility boilers; transport properties of scales with complex defect structures; observations of whiskers and pyramids during high temperature corrosion of iron in SO2; corrosion and creep of alloy 800H under simulated coal gasification conditions; microstructural changes of HK 40 cast alloy caused by exploitation in tubes in steam reformer installation; microstructural changes during exposure in corrosive environments and their effect on mechanical properties; coatings against carburization; mathematical modeling of carbon diffusion and carbide precipitation in Ni-Cr-based alloys. (MM)

  13. Effect of Pseudomonas fluorescens on Buried Steel Pipeline Corrosion.

    Science.gov (United States)

    Spark, Amy J; Law, David W; Ward, Liam P; Cole, Ivan S; Best, Adam S

    2017-08-01

    Buried steel infrastructure can be a source of iron ions for bacterial species, leading to microbiologically influenced corrosion (MIC). Localized corrosion of pipelines due to MIC is one of the key failure mechanisms of buried steel pipelines. In order to better understand the mechanisms of localized corrosion in soil, semisolid agar has been developed as an analogue for soil. Here, Pseudomonas fluorescens has been introduced to the system to understand how bacteria interact with steel. Through electrochemical testing including open circuit potentials, potentiodynamic scans, anodic potential holds, and electrochemical impedance spectroscopy it has been shown that P. fluorescens increases the rate of corrosion. Time for oxide and biofilms to develop was shown to not impact on the rate of corrosion but did alter the consistency of biofilm present and the viability of P. fluorescens following electrochemical testing. The proposed mechanism for increased corrosion rates of carbon steel involves the interactions of pyoverdine with the steel, preventing the formation of a cohesive passive layer, after initial cell attachment, followed by the formation of a metal concentration gradient on the steel surface.

  14. Pitting corrosion of copper. An equilibrium - mass transport study

    Energy Technology Data Exchange (ETDEWEB)

    Taxen, C. [Swedish Corrosion Inst., Stockholm (Sweden)

    2002-08-01

    A mathematical model for the propagation of corrosion pits is described and used to calculate the potentials below which copper is immune to pitting. The model uses equilibrium data and diffusion coefficients and calculates the stationary concentration profiles of 26 aqueous species from the bulk water outside a corrosion pit to the site of the metal dissolution. Precipitation of oxides and salts of copper is considered. Studied conditions include water compositions from tap waters to seawater at the temperatures 25 deg C and 75 deg C. Carbonate and sulphate are aggressive towards copper because of complex formation with divalent copper. Carbonate is less aggressive in a corrosion pit than outside at the pH of the bulk. Carbonate carries acidity out from the pit, favours oxide formation and may prevent the initiation of acidic corrosion pits. The concentration profiles are used to estimate the maximum propagation rates for a corrosion pit. A high potential is found to be the most important factor for the rate of propagation. The levels of potential copper can sustain, as corrosion potentials are discussed in terms of the stability of cuprous oxide as a cathode material for oxygen reduction relative to non-conducting cupric phases.

  15. Early corrosion monitoring of prestressed concrete piles using acoustic emission

    Science.gov (United States)

    Vélez, William; Matta, Fabio; Ziehl, Paul H.

    2013-04-01

    The depassivation and corrosion of bonded prestressing steel strands in concrete bridge members may lead to major damage or collapse before visual inspections uncover evident signs of damage, and well before the end of the design life. Recognizing corrosion in its early stage is desirable to plan and prioritize remediation strategies. The Acoustic Emission (AE) technique is a rational means to develop structural health monitoring and prognosis systems for the early detection and location of corrosion in concrete. Compelling features are the sensitivity to events related to micro- and macrodamage, non-intrusiveness, and suitability for remote and wireless applications. There is little understanding of the correlation between AE and the morphology and extent of early damage on the steel surface. In this paper, the evidence collected from prestressed concrete (PC) specimens that are exposed to salt water is discussed vis-à-vis AE data from continuous monitoring. The specimens consist of PC strips that are subjected to wet/dry salt water cycles, representing portions of bridge piles that are exposed to tidal action. Evidence collected from the specimens includes: (a) values of half-cell potential and linear polarization resistance to recognize active corrosion in its early stage; and (b) scanning electron microscopy micrographs of steel areas from two specimens that were decommissioned once the electrochemical measurements indicated a high probability of active corrosion. These results are used to evaluate the AE activity resulting from early corrosion.

  16. A Review on Dental Amalgam Corrosion and Its Consequences

    Directory of Open Access Journals (Sweden)

    M Fathi

    2004-02-01

    Full Text Available Dental amalgam is still the most useful restorative material for posterior teeth and has been successfully used for over a century. Dental amalgam has been widely used as a direct filling material due to its favorable mechanical properties as well as low cost and easy placement. However, the mercury it contains raises concerns about its biological toxicity and environmental hazard. Although in use for more than 150 years, dental amalgam has always been suspected more or less vigorously due to its alleged health hazard. Amalgam restorations often tarnish and corrode in oral environment. Corrosion of dental amalgam can cause galvanic action. Ion release as a result of corrosion is most important. Humans are exposed to mercury and other main dental metals via vapor or corrosion products in swallowed saliva and also direct absorption into blood from oral mucosa. During recent decades the use of dental amalgam has been discussed with respect to potential toxic effects of mercury components. In this article, the mechanisms of dental amalgam corrosion are described and results of researches are reviewed. It finally covers the corrosion of amalgams since this is the means by which metals, including mercury, can be released within oral cavity. Keywords: Dental amalgam, Amalgam corrosion, Biocompatibility, Mercury release, Amalgam restoration

  17. Microencapsulation of Self Healing Agents for Corrosion Control Coatings

    Science.gov (United States)

    Jolley, S. T.; Li, W.; Buhrow, J. W.; Calle, L. M.

    2011-01-01

    Corrosion, the environmentally induced degradation of materials, is a very costly problem that has a major impact on the global economy. Results from a 2-year breakthrough study released in 2002 by the U.S. Federal Highway Administration (FHWA) showed that the total annual estimated direct cost associated with metallic corrosion in nearly every U.S. industry sector was a staggering $276 billion, approximately 3.1% of the nation's Gross Domestic Product (GOP). Corrosion protective coatings are widely used to protect metallic structures from the detrimental effects of corrosion but their effectiveness can be seriously compromised by mechanical damage, such as a scratch, that exposes the metallic substrate. The incorporation of a self healing mechanism into a corrosion control coating would have the potential to significantly increase its effectiveness and useful lifetime. This paper describes work performed to incorporate a number of microcapsule-based self healing systems into corrosion control coatings. The work includes the preparation and evaluation of self-healing systems based on curable epoxy, acrylate, and siloxane resins, as well as, microencapsulated systems based on passive, solvent born, healing agent delivery. The synthesis and optimization of microcapsule-based self healing systems for thin coating (less than 100 micron) will be presented.

  18. Corrosion aspects in reprocessing technology

    International Nuclear Information System (INIS)

    Fauvet, P.; Pinard Legry, G.

    1992-01-01

    This paper presents two examples illustrating the importance of the physicochemical conditions existing at the metal-medium interface on the corrosion behaviour of materials utilized in spent fuel reprocessing plants: corrosion of a stainless steel in the presence of nitric acid condensates, which is much more severe than in the liquid bulk; behaviour of zirconium, which has an outstanding corrosion resistance in nitric acid, but may suffer depassivation in drastic conditions (not existing in reprocessing plants), with the consequence of a loss of the protective effect of the zirconia passive layer

  19. Cracking and corrosion recovery boiler

    Energy Technology Data Exchange (ETDEWEB)

    Suik, H. [Tallinn Technical University, Horizon Pulp and Paper, Tallinn (Estonia)

    1998-12-31

    The corrosion of heat surfaces and the cracking the drums are the main problems of the recovery boiler. These phenomena have been appeared during long-term operation of boiler `Mitsubishi - 315` erected at 1964. Depth of the crack is depending on the number of shutdowns and on operation time. Corrosion intensity of different heat surfaces is varying depend on the metal temperature and the conditions at place of positioning of tube. The lowest intensity of corrosion is on the bank tubes and the greatest is on the tubes of the second stage superheater and on the tubes at the openings of air ports. (orig.) 5 refs.

  20. Worldwide Experience with Erosion of the Magnetic Sphincter Augmentation Device.

    Science.gov (United States)

    Alicuben, Evan T; Bell, Reginald C W; Jobe, Blair A; Buckley, F P; Daniel Smith, C; Graybeal, Casey J; Lipham, John C

    2018-04-17

    The magnetic sphincter augmentation device continues to become a more common antireflux surgical option with low complication rates. Erosion into the esophagus is an important complication to recognize and is reported to occur at very low incidences (0.1-0.15%). Characterization of this complication remains limited. We aim to describe the worldwide experience with erosion of the magnetic sphincter augmentation device including presentation, techniques for removal, and possible risk factors. We reviewed data obtained from the device manufacturer Torax Medical, Inc., as well as the Manufacturer and User Facility Device Experience (MAUDE) database. The study period was from February 2007 through July 2017 and included all devices placed worldwide. In total, 9453 devices were placed and there were 29 reported cases of erosions. The median time to presentation of an erosion was 26 months with most occurring between 1 and 4 years after placement. The risk of erosion was 0.3% at 4 years after device implantation. Most patients experienced new-onset dysphagia prompting evaluation. Devices were successfully removed in all patients most commonly via an endoscopic removal of the eroded portion followed by a delayed laparoscopic removal of the remaining beads. At a median follow-up of 58 days post-removal, there were no complications and 24 patients have returned to baseline. Four patients reported ongoing mild dysphagia. Erosion of the LINX device is an important but rare complication to recognize that has been safely managed via minimally invasive approaches without long-term consequences.

  1. Critical Study of Corrosion Damaged Concrete Structures

    OpenAIRE

    Sallehuddin Shah Ayop; John Cairns

    2013-01-01

    Corrosion of steel reinforcement in concrete is one of the major problems with respect to the durability of reinforced concrete structures. The degradation of the structure strength due to reinforcement corrosion decreases its design life. This paper presents the literature study on the influence of the corrosion on concrete structure starting from the mechanism of the corrosion until the deterioration stage and the structural effects of corrosion on concrete structures.

  2. Corrosion and corrosion fatigue of airframe aluminum alloys

    Science.gov (United States)

    Chen, G. S.; Gao, M.; Harlow, D. G.; Wei, R. P.

    1994-01-01

    Localized corrosion and corrosion fatigue crack nucleation and growth are recognized as degradation mechanisms that effect the durability and integrity of commercial transport aircraft. Mechanically based understanding is needed to aid the development of effective methodologies for assessing durability and integrity of airframe components. As a part of the methodology development, experiments on pitting corrosion, and on corrosion fatigue crack nucleation and early growth from these pits were conducted. Pitting was found to be associated with constituent particles in the alloys and pit growth often involved coalescence of individual particle-nucleated pits, both laterally and in depth. Fatigue cracks typically nucleated from one of the larger pits that formed by a cluster of particles. The size of pit at which fatigue crack nucleates is a function of stress level and fatigue loading frequency. The experimental results are summarized, and their implications on service performance and life prediction are discussed.

  3. Assessing resistance of stabilized corrosion resistant steels to intergranular corrosion

    International Nuclear Information System (INIS)

    Karas, A.; Cihal, V. Jr.; Vanek, V.; Herzan, J.; Protiva, K.; Cihal, V.

    1987-01-01

    Resistance to intergranular corrosion was determined for four types of titanium-stabilized steels from the coefficients of stabilization efficiency according to the degree the chemical composition was known. The ATA SUPER steel showed the highest resistance parameter value. The resistance of this type of steel of a specific composition, showing a relatively low value of mean nitrogen content was compared with steel of an optimized chemical composition and with low-carbon niobium stabilized, molybdenum modified steels. The comparison showed guarantees of a sufficient resistance of the steel to intergranular corrosion. The method of assessing the resistance to intergranular corrosion using the calculation of the minimum content of Cr', i.e., the effective chromium content, and the maximum effective carbon content C' giving the resistance parameter k seems to be prospective for practical use in the production of corrosion resistant steels. (author). 1 tab., 5 figs., 15 refs

  4. Stress-Corrosion Interactions in Zr-Based Bulk Metallic Glasses

    Directory of Open Access Journals (Sweden)

    Petre Flaviu Gostin

    2015-07-01

    Full Text Available Stress-corrosion interactions in materials may lead to early unpredictable catastrophic failure of structural parts, which can have dramatic effects. In Zr-based bulk metallic glasses, such interactions are particularly important as these have very high yield strength, limited ductility, and are relatively susceptible to localized corrosion in halide-containing aqueous environments. Relevant features of the mechanical and corrosion behavior of Zr-based bulk metallic glasses are described, and an account of knowledge regarding corrosion-deformation interactions gathered from ex situ experimental procedures is provided. Subsequently the literature on key phenomena including hydrogen damage, stress corrosion cracking, and corrosion fatigue is reviewed. Critical factors for such phenomena will be highlighted. The review also presents an outlook for the topic.

  5. U.S. Nuclear Regulatory Commission Corrosion Programme for High-Level Nuclear Waste

    International Nuclear Information System (INIS)

    Ahn, T.M.

    2003-01-01

    The corrosion programme of the U.S. Nuclear Regulatory Commission (NRC) for the evaluation of the engineered barriers to be emplaced for the geological disposal of high-level radioactive waste (HLW) is reviewed. The risk-informed, performance-based regulation established by NRC for the potential licensing of the proposed repository at Yucca Mountain, Nevada is introduced and resolution methods for HLW technical issues are discussed. Examples of the approach adopted for the resolution of issues related to the degradation of engineered barriers as a result of corrosion are presented including uniform corrosion, localised corrosion, and stress corrosion cracking of HLW container materials. The use of analogues to provide additional lines of evidence to the performance evaluations is addressed. Finally, overall NRC activities in waste package corrosion studies are summarised. (author)

  6. Hanford Double Shell Waste Tank Corrosion Studies - Final Report FY2015

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, R. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wyrwas, R. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-01

    During FY15, SRNL performed corrosion testing that supported Washington River Protection Solutions (WRPS) with their double shell tank (DST) integrity program. The testing investigated six concerns including, 1) the possibility of corrosion of the exterior of the secondary tank wall; 2) the effect of ammonia on vapor space corrosion (VSC) above waste simulants; 3) the determination of the minimum required nitrite and hydroxide concentrations that prevent pitting in concentrated nitrate solutions (i.e., waste buffering); 4) the susceptibility to liquid air interface (LAI) corrosion at proposed stress corrosion cracking (SCC) inhibitor concentrations; 5) the susceptibility of carbon steel to pitting in dilute solutions that contain significant quantities of chloride and sulfate; and 6) the effect of different heats of A537 carbon steel on the corrosion response. For task 1, 2, and 4, the effect of heat treating and/ or welding of the materials was also investigated.

  7. Corrosion protection of aluminum by silane-based surface treatment

    Science.gov (United States)

    Song, Jun

    The possibility of using silane coupling agents as replacements for chromate treatments was investigated for aluminum substrates. In order to understand the influence of deposition parameters on silane film formation, pure Al substrates were used to study the interaction between silane coupling agents and aluminum surfaces. The silane films formed on pure A1 substrates from aqueous solutions were characterized by ellipsometry, contact angle measurements, reflection absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and Time-of Flight Secondary Ion Mass Spectrometry. The deposition parameters studied include solution concentration, solution dipping time and pH value of the applied solution. It appears that silane film formation involved a true equilibrium of hydrolysis and condensation in aqueous solution. It has been found that the silane film thickness obtained depends primarily on the solution concentration and is independent of the solution dipping time. The molecular orientation of the applied silane film is determined by the pH value of the applied silane solution and the isoelectic point of the metal substrates. The deposition window in terms of pH value for A1 substrates is between 4 and 7. The total surface energy of silane-coated A1 substrate decreases with film aging time, the decreased rate, however, is determined by the nature of silane coupling agents. Based on the results obtained above, a pretreatment, which involved two-step bis-(triethoxysilyl) ethane and gamma-aminopropyltriethoxysilane, was developed for Al substrates with commercial polyester and polyurethane paints. The results of salt spray testing, cyclic corrosion testing, and electrochemical impedance spectroscopy showed that this treatment provided the same level of corrosion performance as the treatment of phosphating plus a final chromate rinse. The likely reasons for excellent performance are discussed in terms of the physical and chemical characteristics of the

  8. Mapping monthly rainfall erosivity in Europe

    DEFF Research Database (Denmark)

    Ballabio, C; Meusburger, K; Klik, A

    2017-01-01

    Rainfall erosivity as a dynamic factor of soil loss by water erosion is modelled intra-annually for the first time at European scale. The development of Rainfall Erosivity Database at European Scale (REDES) and its 2015 update with the extension to monthly component allowed to develop monthly and...... events. Consequently, spatio-temporal mapping of rainfall erosivity permits to identify the months and the areas with highest risk of soil loss where conservation measures should be applied in different seasons of the year....... and seasonal R-factor maps and assess rainfall erosivity both spatially and temporally. During winter months, significant rainfall erosivity is present only in part of the Mediterranean countries. A sudden increase of erosivity occurs in major part of European Union (except Mediterranean basin, western part...... to Eastern Europe. The maps also show a clear delineation of areas with different erosivity seasonal patterns, whose spatial outline was evidenced by cluster analysis. The monthly erosivity maps can be used to develop composite indicators that map both intra-annual variability and concentration of erosive...

  9. Ornamental landscaping for water erosion control at the federal ...

    African Journals Online (AJOL)

    Water erosion causes serious problems in the environment. The condition is accelerated by the reduction of vegetation resulting from indiscriminate logging of timber and other deforestation activities, which may include the slash and burn method of land preparation and continuous cropping on a particular land over time.

  10. Factors affecting soil erosion in Beijing mountain forestlands

    African Journals Online (AJOL)

    ajl yemi

    2011-11-28

    Nov 28, 2011 ... estimate soil erosion under different forest conditions including regions, vegetation type, and stand density as influenced by ... health. The anti-scouring feature of the forest land soil is considered to be an important part of the assessment as such feature help soil resist from being washed. In the. 1960s, Zhu ...

  11. Minimizing post-fire erosion using rainwater harvesting practices

    Science.gov (United States)

    P. R. Garcia-Chevesich; R. Valdes; D. Neary; R. Pizarro

    2015-01-01

    Though wildfires can lead to tremendous rates of soil erosion, they also have several beneficial effects on natural areas. Plants in ecosystems that are susceptible to wildfires often survive through adaptation processes that include physical protection against heat, increased growth after a wildfire event and production of flammable materials that stimulate fire and...

  12. Validating and improving interrill erosion equations.

    Science.gov (United States)

    Zhang, Feng-Bao; Wang, Zhan-Li; Yang, Ming-Yi

    2014-01-01

    Existing interrill erosion equations based on mini-plot experiments have largely ignored the effects of slope length and plot size on interrill erosion rate. This paper describes a series of simulated rainfall experiments which were conducted according to a randomized factorial design for five slope lengths (0.4, 0.8, 1.2, 1.6, and 2 m) at a width of 0.4 m, five slope gradients (17%, 27%, 36%, 47%, and 58%), and five rainfall intensities (48, 62.4, 102, 149, and 170 mm h(-1)) to perform a systematic validation of existing interrill erosion equations based on mini-plots. The results indicated that the existing interrill erosion equations do not adequately describe the relationships between interrill erosion rate and its influencing factors with increasing slope length and rainfall intensity. Univariate analysis of variance showed that runoff rate, rainfall intensity, slope gradient, and slope length had significant effects on interrill erosion rate and that their interactions were significant at p = 0.01. An improved interrill erosion equation was constructed by analyzing the relationships of sediment concentration with rainfall intensity, slope length, and slope gradient. In the improved interrill erosion equation, the runoff rate and slope factor are the same as in the interrill erosion equation in the Water Erosion Prediction Project (WEPP), with the weight of rainfall intensity adjusted by an exponent of 0.22 and a slope length term added with an exponent of -0.25. Using experimental data from WEPP cropland soil field interrill erodibility experiments, it has been shown that the improved interrill erosion equation describes the relationship between interrill erosion rate and runoff rate, rainfall intensity, slope gradient, and slope length reasonably well and better than existing interrill erosion equations.

  13. Validating and Improving Interrill Erosion Equations

    Science.gov (United States)

    Zhang, Feng-Bao; Wang, Zhan-Li; Yang, Ming-Yi

    2014-01-01

    Existing interrill erosion equations based on mini-plot experiments have largely ignored the effects of slope length and plot size on interrill erosion rate. This paper describes a series of simulated rainfall experiments which were conducted according to a randomized factorial design for five slope lengths (0.4, 0.8, 1.2, 1.6, and 2 m) at a width of 0.4 m, five slope gradients (17%, 27%, 36%, 47%, and 58%), and five rainfall intensities (48, 62.4, 102, 149, and 170 mm h−1) to perform a systematic validation of existing interrill erosion equations based on mini-plots. The results indicated that the existing interrill erosion equations do not adequately describe the relationships between interrill erosion rate and its influencing factors with increasing slope length and rainfall intensity. Univariate analysis of variance showed that runoff rate, rainfall intensity, slope gradient, and slope length had significant effects on interrill erosion rate and that their interactions were significant at p = 0.01. An improved interrill erosion equation was constructed by analyzing the relationships of sediment concentration with rainfall intensity, slope length, and slope gradient. In the improved interrill erosion equation, the runoff rate and slope factor are the same as in the interrill erosion equation in the Water Erosion Prediction Project (WEPP), with the weight of rainfall intensity adjusted by an exponent of 0.22 and a slope length term added with an exponent of −0.25. Using experimental data from WEPP cropland soil field interrill erodibility experiments, it has been shown that the improved interrill erosion equation describes the relationship between interrill erosion rate and runoff rate, rainfall intensity, slope gradient, and slope length reasonably well and better than existing interrill erosion equations. PMID:24516624

  14. Mg-7Gd-5Y-Nd-Zr Alloy Plate Corrosion-resistance Property to Chloride Ion

    Science.gov (United States)

    Jin, Ni Na Zhu Ruanli Zhang

    Rare earth Mg alloy has aroused increasing attention in aviation, spaceflight, war industry application fields; however, its poor corrosion-resistance restricted its wide range of application. For Mg-7Gd-5Y-Nd-Zr extruding plate, the grain orientation and size are different in three planes, which is extruding plane (surface), side plane, and cross-section plane. Microstructure may lead to the variation of corrosion resistant to marine climate environment. The corrosion resistance of chloride ion in three different planes of rare earth Mg plate was studied. The immersion and dynamic potential polarization curves in 3.5 wt. % concentration of sodium chloride solution were used to analysis and compare electrochemical characteristics among the three planes. Optical microscope was employed to observe the microstructure of Mg alloy before and after the chloride ion erosion. The X-ray diffraction was used to determine its corrosion product. The results show that corrosion-resistance properties of the three planes (surface, side and cross section) are different. Pitting corrosion are mainly characteristics and corrosion product is magnesium hydroxide. The different resistant properties of three planes are mainly attributed to different grain size and orientation of the different planes.

  15. Corrosion test on candidate waste package basket materials for the Yucca Mountain project

    International Nuclear Information System (INIS)

    Van Konynenburg, R.A.; Curtis, P.G.

    1996-01-01

    A scoping corrosion test was performed on candidate waste package basket materials in order to assist in selecting materials for package design and to help in designing longer-term corrosion tests. The corrosion solution was buffered near pH4, was in contact with air, and contained chemical species expected to be produced by radiolysis. The test was conducted at 90 C for 96 hours. Samples included aluminum-, copper-, stainless steel-, and zirconium-based metallic materials and several ceramics, incorporating neutron absorber elements. Sample weight losses and solution chemical changes were measured. Both corrosion of the host materials and dissolution of the neutron absorber elements were studied

  16. Tracing correlations of corrosion products and microclimate data on outdoor bronze monuments by Principal Component Analysis

    International Nuclear Information System (INIS)

    Polikreti, Kyriaki; Argyropoulos, Vassilike; Charalambous, Demetres; Vossou, Aggelina; Perdikatsis, Vassilis; Apostolaki, Chryssa

    2009-01-01

    Although the corrosion of outdoor bronzes has been extensively studied for the last decades, there is no quantitative correlation of corrosion products to microclimatic factors. The present work aims to demonstrate how Principal Component Analysis (PCA) can serve this purpose. Thirty corrosion product samples were collected from the bronze monument of Theodoros Kolokotronis (Nafplio, Greece) and analysed using X-Ray Diffractometry (XRD). The quantitative XRD data together with data on surface orientation and exposure to rain or wind were treated by PCA and three distinct groups were found. Each group includes samples of similar composition and microclimate characteristics showing that PCA may give useful information on corrosion mechanisms.

  17. Exfoliation Corrosion and Pitting Corrosion and Their Role in Fatigue Predictive Modeling: State-of-the-Art Review

    Directory of Open Access Journals (Sweden)

    David W. Hoeppner

    2012-01-01

    Full Text Available Intergranular attack (IG and exfoliation corrosion (EC have a detrimental impact on the structural integrity of aircraft structures of all types. Understanding the mechanisms and methods for dealing with these processes and with corrosion in general has been and is critical to the safety of critical components of aircraft. Discussion of cases where IG attack and exfoliation caused issues in structural integrity in aircraft in operational fleets is presented herein along with a much more detailed presentation of the issues involved in dealing with corrosion of aircraft. Issues of corrosion and fatigue related to the structural integrity of aging aircraft are introduced herein. Mechanisms of pitting nucleation are discussed which include adsorption-induced, ion migration-penetration, and chemicomechanical film breakdown theories. In addition, pitting corrosion (PC fatigue models are presented as well as a critical assessment of their application to aircraft structures and materials. Finally environmental effects on short crack behavior of materials are discussed, and a compilation of definitions related to corrosion and fatigue are presented.

  18. Countermeasures to corrosion on water walls. Part 2; Aatgaerder mot eldstadskorrosion paa panntuber. Etapp 2

    Energy Technology Data Exchange (ETDEWEB)

    Storesund, Jan; Elger, Ragna; Nordling, Magnus; Viklund, Peter

    2011-01-15

    Background: The problems with water wall corrosion have been accelerating over the last years. There are a number of reasons for this. Originally mild steels were successfully used in power plant water walls. The magnetite layer that forms at the fire side of the tubes when the boiler is taken into operation protected from corrosion attack. The fuels at that time (oil, coal, gas) were not able to break down the magnetite by corrosion. In addition, there were no restrictions for pollutions and for the combustion itself that could contribute to corrosion attack. The usage of fossil fuels has decreased substantially over the last 25 years, not least by environmental reasons. As a replacement a number of different kinds of bio mass fuels are used. These are typically more or less corrosive and the magnetite layers are attacked. The corrosion is often supported by reducing conditions as a result of the restrictions of the NO{sub x}-pollution. Also the waste fuelled boilers have huge corrosion problems. This has been the case for the last 25 years but nowadays the number of such plants is so much higher and the service data have been turned up. Corrosion protection of the water wall tubes started to be successful in the beginning of the seventies by the introduction of the composite tube. Such tubes are fabricated by mild steel or a low alloy core and corrosion resistant austenite steel or nickel base as an about 2 mm thick corrosion protective coating. Weld cladding of the water wall tubes was introduced in the 1980's as a significantly cheaper alternative to the composite tubes. Thermal spraying and refractory protection are other methods. These corrosion protection methods have not always been effective. For example, depending on incorrect materials selection, incorrect performance and incorrect method selection for the current corrosion or erosion attack. Therefore, there is a need for increased knowledge of which protection method and material that will work

  19. Repassivation potentials determination of crevice corrosion of alloy in Chloride solutions

    International Nuclear Information System (INIS)

    Rincon Ortiz, Mauricio

    2009-01-01

    Alloy 22 (UNS N06022) belongs to the Ni-Cr-Mo family and it is highly resistant to general and localized corrosion, but it may suffer crevice corrosion in aggressive environmental conditions, such as high chloride concentration, high applied potential and high temperature. Alloy 22 is one of the candidates to be considered for the outer corrosion-resistant shell of high-level nuclear waste containers. It is assumed that localized corrosion will only occur when the corrosion potential (E CORR ) is equal or higher than the crevice corrosion repassivation potential (E R,CREV ). This parameter is obtained by different electrochemical techniques using artificially creviced specimens. These techniques include cyclic potentiodynamic polarization (CPP) curves, Tsujikawa-Hisamatsu electrochemical (THE) method or other non-standardized methods. Recently, as a variation of THE method, the PD-GS-PD technique was introduced. The aim of the present work was to determine reliable critical potentials for crevice corrosion of Alloy 22 in pure chloride solutions at 90 C degrees. Conservative methodologies (which include extended potentiostatic steps) were applied for determining protection potentials below which crevice corrosion cannot initiate and propagate. Results from PD-GS-PD technique were compared with those from these methodologies in order to assess their reliability. Results from the CPP and the THE methods were also considered for comparison. The repassivation potentials from the PD-GS-PD technique were conservative and reproducible, and they did not depend on the amount of previous crevice corrosion propagation in the studied conditions. (author)

  20. Stress corrosion cracking mitigation by ultrasound induced cavitation technique

    International Nuclear Information System (INIS)

    Fong, C.; Lee, Y.C.; Yeh, T.K.

    2014-01-01

    Cavitation is usually considered as a damaging mechanism under erosion corrosion condition. However, if used appropriately, cavitation can be applied as a peening technique for surface stress modification process. The aim of surface stress modification is to alter the stress state of processed surface through direct or indirect thermo-mechanical treatments to reduce cracking problems initiated from surface. Ultrasonic devices are used to generate cavitation bubbles which when collapse will produce high intensity shock waves and high velocity micro-jet streams. The cavitation impact when properly controlled will create plastically deformed compressive layers in nearby surfaces and minimize cracking susceptibility in corrosive environments. This study is to investigate the effectiveness of Ultrasound Induced Cavitation (UIC) technique in surface stress improvement. Ultrasonic cavitation treatment of SS304 stainless steel under pure water is carried out with different controlling parameters. The cavitation impact on SS304 surface is measured in terms of surface roughness, surface strain, hardness, and microstructural characteristics. The in-depth residual stress distribution and crack mitigation effect are also evaluated. Test result indicates ultrasound induced cavitation treatment only has minor effect on surface physical characteristics. The extent of compressive stress produced on top surface exceeds the yield strength and can reach a depth above 150 μm. The maximum surface strain measured is generally below 20%, which is not considered detrimental to accelerate crack initiation. Stress corrosion verification tests show UIC treatment is capable in preventing environmental assisted cracking of stainless steels in severely corrosive conditions. In view of the test results, UIC technique has demonstrated to be a low cost, low contaminating, and effective surface stress improvement technology. (author)